"Container for carrying out medical or veterinary procedures and related calibration method"

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Technical Field

The present invention relates to a container for carrying out medical or veterinary procedures.

The invention fits into the technical field of medical devices for collecting 5 liquid biological samples, for example vacuum test tubes, and more precisely it relates to a container capable of maintaining the amount of a liquid biological sample collected at any altitude substantially constant or, at the same elevation, increasing the amount of the liquid biological sample collected, where this becomes necessary.

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State of the Art

The collection of liquid biological samples with vacuum tubes is a well- established procedure in the medical and veterinary fields.

These tubes, also commonly called test tubes, have different dimensions 15 so as to be able to contain different amounts of liquid biological sample (3 imL, 8 ml ).

Vacuum test tubes are sold sealed in order to avoid contamination by external contaminating agents and to preserve the specific degree of vacuum created inside them.

20 The distinctive feature of this type of test tubes, in fact, is the ability to enable the collection of a liquid biological sample, typically blood, thanks to the difference in pressure between the pressure inside the test tube and the patient's internal pressure, which coincides substantially with the atmospheric pressure of the place where the sample is collected.

25 As long as the pressure inside the test tube is lower than the patient's internal pressure and thus lower than the atmospheric pressure of the place where the sample is collected, the liquid biological sample, typically blood, will flow into the test tube until the two pressures are substantially equal to each other.

The main drawback of the vacuum test tubes used in the medical and veterinary fields, according to the prior art briefly described above, occurs when liquid biological samples are collected at increasing altitudes.

In fact, the degree of vacuum set inside test tubes in order to bring about a pressure differential (between the inside of the test tube and the patient's body) such as to enable the collection of a given amount of a liquid biological sample is calculated at the standard atmospheric pressure (1013.25 hPa).

However, atmospheric pressure changes with variations in elevation. In fact, as the elevation relative to sea level increases, the atmospheric pressure decreases and thus the difference between the patient's internal pressure and the pressure inside the test tube falls below a minimum threshold value necessary for collecting the pre-established amount of the liquid biological sample, with a consequent decrease in the final volume of the collected sample.

Disadvantageously, this circumstance reduces the amount of the biological sample useful for the analyses it is intended to carry out.

Moreover, the test tubes made according to the prior art have a further relevant drawback, as explained in the paragraphs that follow.

The vacuum test tubes present on the market contain additives, for example blood thinners, procoagulants and various inhibitors suitable for mixing with the amount of the liquid biological product collected. The amount of additives present in a vacuum container is precisely calibrated based on the amount of liquid biological sample it is planned to collect. Disadvantageously, therefore, a decrease in the amount of the liquid biological sample collected brings about a variation in the quantitative ratio between additives and the biological sample itself with the consequent alteration of the results of the analyses it is intended to perform. Object of the invention

In this context, the technical task of the present invention is to propose a container for carrying out medical or veterinary procedures that overcomes the above-mentioned drawbacks of the prior art.

In particular, it is an object of the present invention to provide a container that is capable of maintaining the amount of a liquid biological sample collected constant, irrespective of the altitude at which the collection of the liquid biological sample takes place.

Another object of the present invention is to provide a container that is capable of maintaining a constant quantitative ratio between the liquid biological sample collected and the additives present inside the test tube itself.

Another object of the present invention is to provide a container that is capable of enabling, at the same elevation, the collection of a greater amount of a liquid biological sample, where this becomes necessary.

The stated technical task and specified objects are substantially achieved by a container for carrying out medical or veterinary procedures which comprises the technical features set forth in the independent claim. The dependent claims correspond to further advantageous aspects of the invention.

The invention relates to a container for carrying out medical or veterinary procedures which comprises: a reservoir having a closed end and an open end; a stopper at least partially inserted sealingly in the reservoir at the open end to maintain a pre-established initial pressure value of a gaseous fluid present inside the reservoir. In particular, the stopper delimits an initial volume inside the reservoir and is shaped in such a manner that a conduit can pass through it so as to enable the reservoir to be filled with a liquid biological sample.

The container comprises a movement member that is associated with the reservoir and operatively active on the stopper so as to move the latter between at least a first operative position, in which it delimits said initial volume, and at least a second stable operative position, in which the stopper delimits a final volume that is larger or smaller than the initial volume so as to decrease or increase the pressure value of the gaseous fluid present inside the reservoir, respectively.

According to one aspect of the invention, the movement member is solidly constrained to the stopper and is slidably movable along a direction of extension of the reservoir at least between two operative configurations corresponding, respectively, to the first and second operative positions assumed by the stopper to delimit the initial and final volumes.

According to a further aspect of the invention, the movement member comprises a hollow body, having a housing seat suitable for receiving a portion of the stopper, and a first coupling means fashioned on a portion of the hollow body and suitable for engagement in a corresponding second coupling means fashioned on a portion of the reservoir.

The first coupling means preferably comprises a thread fashioned on the hollow body, whereas the second coupling means comprises a counter- thread fashioned on the reservoir and that at least partially faces the thread present on the hollow body, whereby the hollow body is screwed and unscrewed in such a manner as to be slidably movable along a direction of extension of the reservoir.

According to one aspect of the invention, the reservoir has a plurality of marks, each of which referring to positions in which the stopper stops so as to delimit volumes inside the reservoir.

Advantageously, the marks present on the reservoir, preferably equidistant from one another, provide a visual point of reference for identifying exactly where the stopper is positioned following its movement. Furthermore, given that the first mark refers - preferably - to the position in which the stopper delimits the initial volume, knowing the number of marks comprised between the first one and the one in which the stopper stops makes it possible to verify how much the internal volume of the reservoir has increased and thus to estimate how much the degree of vacuum has increased (that is, how much the internal pressure has decreased). According to a further aspect of the invention, in fact, having initially pre- established a correlation between the usable internal volume and the degree of vacuum set inside the test tube it is possible to estimate the pressure inside the container starting from the position assumed by the stopper.

The reservoir is preferably made of a transparent material so as to enable the position in which the stopper stops inside the reservoir to be seen directly with respect to the plurality of marks.

Alternatively, each mark of said plurality of marks corresponds to a position in which a reference portion of the movement member stops during movement of the stopper.

According to another aspect of the invention, the stopper has a section that is perforable and of reduced thickness so as to enable a conduit that can be associated therewith to penetrate into the volume delimited by the stopper when it is stopped in a specific position to enable the reservoir to be filled with the liquid biological sample.

The stopper preferably has a section that, in the direction of extension of the reservoir, is substantially H-shaped, so as to define two cavities of the stopper arranged along the direction of extension of the reservoir. In particular, the cavities are interspaced by the perforable section of reduced thickness.

Advantageously, the H-shaped section which defines the two cavities, together with the perforable section of reduced thickness, enables easy perforation by means of an external needle of standard length. In fact, the presence of the two cavities reduces the thickness of the stopper along the longitudinal direction of extension thereof and enables the needle tip to be introduced into the volume of the reservoir and thus to convey the liquid biological sample collected. Additionally, the H-shaped section of the stopper provides the further advantage of facilitating the deformation of the portion of the stopper that presses against the walls of the reservoir, thereby facilitating its movement.

According to another aspect of the invention, the stopper has, on at least one portion of a side surface thereof facing the reservoir, a pattern in relief for reducing the contact zones between said side surface and the reservoir, so as to reduce friction during movement of the stopper and thus enable better sliding thereof during displacement in order to establish the desired pressure gradient.

The pattern in relief preferably comprises a plurality of lines in relief with different orientations and that are incident with respect to each other, preferably with a mesh-type pattern.

The mesh pattern, that is, the overlapping of a first plurality of lines in relief parallel to one another and having a specific first orientation with a second plurality of lines in relief, similarly parallel to one another and having a second orientation opposite the first orientation, has shown to be the preferable one, as it is capable of providing an excellent result.

According to a further aspect of the invention, the thread present on the hollow body extends over a reduced length compared to the length over which the corresponding counter-thread present on the reservoir extends. Advantageously, this feature makes it possible to prevent the stopper from accidentally slipping off the reservoir during movement of the stopper itself.

The thread at the open end of the reservoir and the counter-thread present on the movement member enable the operation of moving the stopper to be simplified. Furthermore, considering that, as already mentioned, the counter-thread of the movement member preferably extends for a smaller length than the length over which the thread of the reservoir extends, the possibility of an accidental opening of the container and thus the consequent risk of dispersing the liquid biological sample collected is considerably reduced. In fact, a portion of the stopper inserted sealingly in the reservoir will maintain the stopper itself connected to the container and thus in the configuration of closure of the open end of the reservoir.

The present invention further relates to a closure device for a container for carrying out medical procedures which comprises a stopper that can be sealingly coupled with a reservoir of a container so as to delimit an initial volume inside the reservoir itself. The stopper is shaped in such a manner that a conduit can pass through it so as to enable the reservoir to be filled with a liquid biological sample. The closure device comprises a hollow body solidly constrained to the stopper and that can be slidably coupled to the container along a direction of extension of the reservoir to move the stopper between at least a first operative position, in which the latter delimits an initial volume inside the reservoir, and at least a second stable operative position, in which the stopper delimits a final volume that is larger or smaller than the initial volume inside the reservoir. The closure device further comprises a first coupling means fashioned on a portion of the hollow body and capable of engaging in a corresponding second coupling means present on a portion of the container.

According to one aspect of the invention, the first coupling means comprises a thread fashioned on the hollow body and that is suitable for engagement with a counter-thread present on a portion of the container, whereby the hollow body, when in use on the container, can be screwed and unscrewed so as to be slidably movable along a direction of extension of the reservoir.

According to another aspect of the invention, the stopper has a perforable section of reduced thickness suitable for having a conduit that can pass through it so as to enable the reservoir to be filled with the liquid biological sample.

According to a further aspect of the invention, the stopper has a section that, in the longitudinal direction of extension of the reservoir, is substantially H-shaped so that a first cavity and a second cavity of the stopper are arranged at opposite ends with respect to said perforable section of reduced thickness.

According to another aspect of the invention, the stopper has, on at least one portion of a side surface thereof that can face the reservoir, a pattern in relief for reducing the contact zones between said side surface and a surface of the reservoir so as to reduce friction during movement of the stopper itself.

The pattern in relief preferably comprises a plurality of lines in relief with different orientations and that are incident with respect to each other, preferably with a mesh-type pattern.

The present invention also relates to a method for calibrating a container of the above-described type. The calibration method comprises the steps of:

- preparing a first test container;

- detecting the atmospheric pressure value;

- detecting the internal pressure value of the gaseous fluid present inside the initial volume of the reservoir;

- moving the stopper until the internal pressure of the gaseous fluid reaches a value such as to define a pre-established pressure gradient between the interior and the exterior of the container, the final position of the stopper corresponding to a final volume inside the reservoir;

- monitoring the internal pressure value of the gaseous fluid during the preceding step of moving the stopper;

- interrupting the displacement of the stopper upon reaching the internal pressure value that achieves the desired pressure gradient value;

- correlating the internal pressure of the fluid and at least one mark, out of a plurality of predefined marks, which visually signals that the final volume has been reached, at which the internal pressure value achieves the desired pressure gradient value; - preparing a second container provided with the same marks;

- collimating the position of the stopper of the second container with the mark that visually signals the final volume, at which the internal pressure value achieves the desired pressure gradient value.

According to one aspect of the invention, the steps of detecting the value of atmospheric pressure and of detecting the internal pressure value of the gaseous fluid present inside the initial volume of the reservoir are repeated at pre-established altitudes so as to correlate the internal pressure of the fluid to at least one mark that visually signals that the final volume has been reached, at which the internal pressure value achieves the desired pressure gradient value.

The application of this calibration method makes it possible to know all of the useful and necessary amounts of the system, i.e. internal pressure, displacement of the stopper and the correlation thereof with the marks.

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Brief description of the drawings

Additional features and advantages of the present invention will become more evident from the approximate and thus non-limiting description of a preferred but non-exclusive embodiment of a container for carrying out medical procedures, as illustrated in the appended drawings, in which:

- figure 1 illustrates an exploded perspective view of a container for carrying out medical procedures;

- figure 2 illustrates a perspective view of the various components of the closure device for a container;

- figure 3 illustrates a perspective view of the closure device in use on a container;

- figure 4 illustrates an exploded longitudinal-section view of a container;

- figure 5 illustrates an overall perspective view of the container in an assembled configuration. With reference to the drawings, they serve solely to illustrate embodiments of the invention with the aim of better clarifying, in combination with the description, the inventive principles of the invention.

* * * * * Detailed description of preferred embodiments of the invention

The present invention relates to a container 1 for carrying out medical or veterinary procedures, which comprises a device that is capable of maintaining the amount of a collected liquid biological sample substantially constant irrespective of the altitude at which it is used.

A container according to the present invention is likewise capable of enabling, at the same elevation, the collection of a larger amount of a liquid biological sample, where this becomes necessary.

With reference to the figures, a container 1 for carrying out medical or veterinary procedures has been generically denoted with the number 1 . In figure 5 it is possible to observe the container 1 in an assembled condition. The other numerical references refer to technical features of the invention which, except for various indications or evident structural incompatibilities, the person skilled in the art will know how to apply to all the variant embodiments described.

As shown in figure 1 , in accordance with the invention, the container 1 for carrying out medical or veterinary procedures comprises a reservoir 2 having a first closed end 2a and a second open end 2b. The reservoir 2, generally for use in the medical or veterinary field, has a cylindrical or slightly conical shape with the closed end 2a in the shape of a hemisphere; however, the possibility of producing a reservoir 2 with different shapes is not ruled out.

The container 1 further comprises a stopper 3 partially inserted sealingly in the reservoir 2 at the open end 2b to maintain a given pressure value inside the reservoir 2 itself, as will become clear below. The stopper 3 is preferably substantially a plug having a circular section suitable for inserting it through the open end 2b into the reservoir 2 and maintaining it in a stable position.

With particular reference to figure 3, the stopper 3 has a transversal dimension substantially equal to the dimension of the passage section of the open end 2b of the reservoir 2. In this manner, the side surface 3a of the stopper 3 and the internal side surface of the reservoir 2 are always in contact, thus preventing the exchange of substances with the surrounding environment.

When coupled to the reservoir 2, the stopper 3 delimits an initial volume inside the reservoir 2 itself which is suitable for containing a gaseous fluid having a predefined pressure value, generally lower than the standard atmospheric pressure at sea level.

For the correct operation of the container 1 , it is necessary to establish a pressure difference (gradient) between the pressure of the gaseous fluid present inside the reservoir 2 and the patient's internal pressure, the latter substantially coinciding with the atmospheric pressure of the place where the liquid biological sample is collected.

The gaseous fluid is preferably sterile air and the pressure thereof inside the reservoir 2 is set during production of the container.

In order to enable collection of the liquid biological sample, the stopper 3 is of the perforable type, for example by an external needle or conduit. In particular, the stopper 3 has a perforable section of reduced thickness, typically a membrane 7 of millimetric thickness, interposed between two cavities 7a, 7b. The stopper 3 is preferably made of a bio-silicone material. With reference to figure 4, the cavities 7a, 7b have - preferably - an identical shape and are arranged along the same direction of extension L of the reservoir 2. In particular, the first cavity 7a extends from one end of the stopper 3 outside the reservoir 2 for a length that is less than the length of the needles normally used for collecting samples, whereas the second cavity 7b extends from the end of the stopper 3 inserted in the reservoir 2. The length of the second cavity 7b, extending towards the cavity 7a, is such as to define the millimetric thickness of the perforable membrane 7. The needle thus inserted through the first cavity 7a is able to reach and perforate the membrane in order to introduce the liquid biological sample into the reservoir 2, thanks to the presence of the second cavity 7b extending up to the membrane 7.

In other words, the stopper 3 has a section which, along the direction of extension L of the reservoir 2, is substantially H-shaped, as shown in figure 4.

With reference to the figures, the container 1 comprises a movement member 4, preferably in the form of a plug cover element, solidly constrained to the stopper 3 and operatively active on the latter so as to move it between at least a first operative position, in which the stopper 3 delimits the initial volume, and at least a second stable operative position, in which the stopper 3 delimits a final volume that is larger or smaller than the initial volume so as to decrease or increase the pressure value of the gaseous fluid present inside the reservoir 2, respectively.

In particular, by moving the stopper in such a way as to increase the final volume inside the reservoir, it is possible to decrease the pressure of the gaseous fluid contained therein and achieve the advantage of maintaining the pressure gradient between the atmospheric pressure of the place where the collection of the sample takes place and the pressure of said gaseous fluid substantially unchanged. As is well known and has already been explained, in fact, the atmospheric pressure decreases with increasing elevations and the invention therefore enables the same amount of liquid biological sample to be collected.

The invention achieves a further important advantage. In fact, if it is necessary to collect a larger amount of a liquid biological sample at the same elevation, it will be possible to move the stopper so as to increase the final volume inside the reservoir, thereby decreasing the pressure of the gaseous fluid, and thus establishing a higher pressure gradient, which facilitates the collection of larger sample amounts. There exist, in fact, particular medical conditions known as polycythemia, which result in a decrease in the ratio between the liquid part and the cellular part of blood, and in which it becomes necessary to maintain an accurate ratio of volumes between the liquid part of the blood and the additive-anticoagulant. This can be obtained, precisely, by increasing the amount of blood aspirated through the container according to the present invention, instead of manually decreasing the amount of additive- anticoagulant, as presently occurs in the prior art, which is disadvantageously inaccurate, slow and not under vacuum.

In accordance with one aspect of the invention, the movement member 4 and the stopper 3 constitute a closure device 100 for the container 1 .

In accordance with one aspect of the invention, the movement member 4 comprises a hollow body 4a that can be slidably coupled to the container 1 along the direction of extension L thereof to move the stopper 3 itself between at least the first operative position, in which it delimits the initial volume, and at least a second stable operative position, in which it delimits a final volume that is larger or smaller than the previous one in order to vary the internal pressure value of the gaseous fluid present in the reservoir 2.

The movement member further comprises a first coupling means 5a capable of engagement in a corresponding second coupling means 5b present on a portion of the reservoir 2.

According to one aspect of the invention, these first and second coupling means 5a, 5b comprise a thread and counter-thread system such that the hollow body 4a can be screwed and unscrewed so as to be slidably movable along a direction of extension L of the reservoir 2 in order to move the stopper 3 in such a way that the latter can assume a stable position defining the volume inside the reservoir 2 and comprised between the above-mentioned first and second operative positions.

Advantageously, in order to prevent unintentional openings of the container 1 , it is envisaged that the thread present on the hollow body 4a extends for a smaller length than the length along which the corresponding counter-thread present on the reservoir 2 extends. Substantially, whereas the counter-thread on the reservoir 2 extends from the open end 2b for a length of, for example, 10 millimetres, the corresponding thread of the hollow body 4a extends for a smaller length beginning at a distance, for example, of about 5 millimetres from the open end of the movement member 4 facing the reservoir 2.

Alternatively, with the same function, the first and second coupling means 5a, 5b can comprise a positioning system defined by a plurality of protrusions disposed on the reservoir 2 along the direction of extension L thereof, preferably equidistant, and by a specific seat present on the hollow body 4a and suitable for receiving and mechanically engaging, by interference, a protrusion so as to define a stable position of the hollow body 4a relative to the reservoir 2. The position is modifiable over time following the application of an external force by an operator on the hollow body 4a, so as to make it slide along the reservoir in discrete steps.

According to a further aspect of the invention, as shown in figure 2, the stopper 3 has, at the top thereof outside the reservoir 2, an edge 33 suitable for defining a stop element to prevent an excessive insertion of the stopper 3 into the reservoir 2.

Furthermore, the edge 33 engages in a housing seat 4b of the hollow body 4a so that the latter is able to move the stopper 3. In particular, according to one aspect of the invention, the housing seat 4b is a recess present along the inner wall of the movement member 4 and shaped so as to fittingly receive the edge 33 of the stopper 3. Alternatively, the housing seat 4b is a projecting abutment extending along a perimeter of the inner wall of the movement member 4 so as to define a rest surface for the edge 33 of the stopper 3 and ensure the correct positioning of the stopper 3 inside the movement member 4 and the necessary constraint for the stopper 3 along the direction L upwards. Referring to the latter possibility, the closure device 100 (figure 3) comprises a cap 9 placed on top of the stopper 3 in such a way as to fittingly close the hollow body 4a. In this manner, the movement member 4 is able to apply a translation force on the stopper 3 as a result of the screwing/unscrewing or in any case sliding action along the direction of extension L of the reservoir 2 exerted by an operator on the hollow body 4a.

Advantageously, the cap 9 has a hole at the first cavity 7a of the stopper 3, said hole having a transversal dimension that is preferably equal to that of the cavity, so as to enable the passage of a needle or a conduit for collecting the liquid biological sample.

In order to facilitate, advantageously, a sliding movement of the stopper 3 on the side walls of the reservoir 2, on at least one portion of the side surface 3a of the stopper 3 there is a pattern in relief 8, preferably with a mesh pattern; in particular, said mesh pattern is defined by a first plurality of lines in relief that are parallel to each other and incident with a second plurality of lines in relief that are parallel to each other and have a different orientation from the first ones.

The pattern in relief 8 decreases the contact zones between the side surface 3a of the stopper 3 and the inner side wall of the reservoir 2 and, consequently, it decreases the sliding friction that is generated during the sliding of the stopper 3.

In order to enable the repeatability of the sample collection operations under the same conditions it is necessary to establish a correlation between the position in which the closure device 100 stops (with reference to the stopper 3 and/or the movement member 4) and the pressure value of the gaseous fluid present inside the container 1 .

For this purpose, on the outer side surface of the reservoir 2 there is a plurality of marks 6, each one referring to the positions in which the stopper 3, or the movement member 4 (solidly constrained to the stopper 3), stops to delimit the internal volume of the reservoir, between the first operative position (initial volume) and the second stable operative position, useful for maintaining the pre-selected pressure gradient. The plurality of marks 6 consists in a plurality of lines parallel to each other, preferably equidistant, arranged in proximity to the open end 2b of the reservoir 2 according to a direction transversal to the direction of extension L of the reservoir 2 itself. A first mark 6 is the visual reference of the initial operative position in which the stopper 3, or the movement member 4, stops in defining the initial volume, and thus the initial pressure of the gaseous fluid present inside the container 1 , whereas the remaining marks 6 refer to different positions in which the stopper 3, or the movement member 4, is able to stop in defining different volumes inside the reservoir 2 in order to maintain the pre-selected pressure gradient.

The reservoir 2 is preferably produced with a transparent material, for example plastic or glass, to enable at least a portion of the stopper 3 to be seen for precise collimation with the corresponding mark 6. Alternatively, in the event that the view of the stopper 3 is limited due to the colour of the reservoir 2 or, for example, because of the liquid biological sample collected, a portion of the movement member 4, solidly constrained to the stopper 3, is taken as a reference with respect to the marks and can be used to indirectly verify the position/movement of the stopper 3 inside the reservoir 2 and thus monitor the variation in the internal volume of the container 1 .

Therefore, the marks 6 are visual references that can be used by the operator to correlate the internal pressure of the container 1 with a specific position of the stopper 3, or a specific volume inside the container 1 . In greater detail, by screwing or unscrewing the movement member 4 - or in any event moving it - the operator applies a movement of the stopper 3 along the direction of extension L of the reservoir 2, respectively, inserting or extracting the stopper from the reservoir itself. Being able to verify the position of the stopper and/or movement member with respect to the marks, the operator is able to monitor the variation in the internal volume of the container 1 and stop the movement of the stopper at a pre- established internal volume. According to the invention, the embodiments in accordance with the following clauses are moreover provided:

Clause 1 . A closure device 100 for a container 1 for carrying out medical procedures, comprising

- a stopper 3 that can be sealingly coupled with a reservoir 2 of a container 1 to delimit an initial volume inside the reservoir 2 itself, said stopper being shaped in such a manner that a conduit can pass through it so as to enable the reservoir to be filled with a liquid biological sample; a hollow body 4a solidly constrained to the stopper 3 and that can be slidably coupled to the container 1 along a direction of extension L of the reservoir 2 to move the stopper 3 between at least a first operative position, in which it delimits an initial volume inside the reservoir 2, and at least a second stable operative position, in which the stopper 3 delimits a final volume that is larger or smaller than the initial volume inside the reservoir;

a first coupling means 5a fashioned on a portion of said hollow body 4a and capable of engagement in a corresponding second coupling means 5b present on a portion of the container 1 .

Clause 2. The closure device 100 according to clause 1 , wherein said first coupling means 5a comprises a thread fashioned on said hollow body 4a and that is suitable for engagement with a counter-thread present on a portion of the container 1 , whereby said hollow body 4a, when in use on the container, can be screwed and unscrewed so as to be slidably movable along a direction of extension L of the reservoir 2.

Clause 3. The closure device 100 according to clause 1 or 2, wherein said stopper 3 has a perforable section 7 of reduced thickness that is suitable for having a conduit that can pass through it so as to enable the reservoir 2 to be filled with the liquid biological sample.

Clause 4. The closure device 100 according to clause 1 , 2 or 3 wherein said stopper 3 has a substantially H-shaped section in the longitudinal direction of extension L of the reservoir 2, whereby a first cavity 7a and a second cavity 7b of said stopper 3 are arranged at opposite ends with respect to said perforable section 7 of reduced thickness.

Clause 5. The closure device 100 according to any one of clauses 1 to 4, wherein said stopper 3 has, on at least one portion of a side surface 3a thereof that can face the reservoir 2, a pattern in relief 8 for reducing the contact zones between said side surface 3a and a surface of the reservoir 2 so as to reduce friction during movement of the stopper 3 itself.

Clause 6. The closure device 100 according to clause 5, wherein said pattern in relief 8 comprises a plurality of lines in relief with different orientations and that are incident with respect to each other, preferably with a mesh pattern.

The subject matter of the present invention also relates to a calibration method for associating a specific internal pressure of the gaseous fluid present inside the container 1 with one or more marks 6 present on the reservoir 2.

The method for calibrating a container 1 for carrying out medical procedures comprises the operative steps of:

a) preparing a first test container;

b) detecting the atmospheric pressure value;

c) detecting the internal pressure value of the gaseous fluid present inside the initial volume of the reservoir 2;

d) moving the stopper 3 until the internal pressure of the gaseous fluid reaches a value such as to define a pre-established pressure gradient between the interior and the exterior of the container 1 , the final position of the stopper corresponding to a final volume inside the reservoir 2;

e) monitoring the internal pressure value of the gaseous fluid during the preceding step of moving the stopper 3; f) interrupting the displacement of the stopper 3 upon reaching the internal pressure value that achieves the desired pressure gradient value;

g) correlating the internal pressure of the fluid and at least one mark 6 which visually signals that the final volume has been reached, at which the internal pressure value achieves the desired pressure gradient value;

h) preparing a second container 1 provided with the same marks 6; i) collimating the position of the stopper 3 of the second container 1 with the mark 6 that visually signals the final volume, at which the internal pressure value achieves the pressure gradient value indicated.

The patient's internal pressure is substantially equal to the atmospheric pressure of the place where the patient is located.

As is well known, the atmospheric pressure varies depending on the altitude of the place and therefore steps a) to i) listed above are repeated at pre-established altitudes. Alternatively, steps a) to i) can be repeated in an environment that simulates the variation of atmospheric pressure with elevation.

In order to perform these measurements, a vacuum gauge is preferably used.

Even more preferably, the vacuum gauge is prepared in accordance with the following procedure:

- connecting a tube, preferably made of polymeric material, by using an adaptor and a reducer;

- connecting a syringe with a "luer" connector for needles to the tube by means of an adaptor and docking means;

- setting the vacuum gauge on the operating mode for measuring the vacuum;

- clearing the value recorded by the vacuum gauge; - determining the dead volume of the measurement system by carrying out the following sub-steps:

^■ making a first measurement, which can provide a first pressure value;

^■ repeating the measurement made in the preceding step, which can provide a second pressure value;

^■ determining the dead volume of the system by calculating the difference between said first pressure value and said second pressure value.

Advantageously, the aforesaid procedure enables a precise calibration of the vacuum gauge to be obtained.

Any modifications or variations which, in the light of the description, are evident to the person skilled in the art, must be considered to fall within the scope of protection established by the present invention, according to considerations of technical equivalence.