BACKGROUND OF THE INVENTION /. Field of the Invention

One or more embodiments of the invention relate generally to apparatus for analyzing liquids, such as body fluids, using labeled molecular affinity binding, such as immuno-chromatography. The present invention further relates to an electronic device for reading the analysis apparatus. More particularly, the invention relates to test strip apparatus for detecting an analyte, such as an antibody or antigen, which may indicate a particular condition, as well as a digital electronic device for reading results from the test strip apparatus.

2. Description of Prior A rt and Related Information

The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to further educate the reader as to additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof to anything stated or implied therein or inferred thereupon.

Labeled molecular affinity binding such as immunochromatographic assays have existed for decades and have proven to be an inexpensive way to screen for various conditions such as abused drugs and other conditions such as pregnancy, cancer, or for single or multiple pathogenic conditions such as HTV infection.

In the point-of-care test (POCT) setting, immunochromatographic assays are typical conducted using lateral flow strip technology as described in May et al., U.S. Pat. No. 5,656,503 incorporated herein by reference. Unfortunately, although they can be fast, inexpensive, and simple-to-use, depending on the type of condition being detected, these tests provide a typical accuracy of between 75% and 95%, falling short of the 99% or above accuracy generally considered to be necessary for a confirmatory test, and providing no objective measure of a quantitative result, i.e. the concentration of a given drug present in the liquid being tested.

The reasons for the insufficient accuracy in many rapid 1VD test devices are primarily due to their current lack of overall higher sensitivity and specificity. Different samples may contain chemicals or particles which intrinsically inhibit the rapid and well mixed liquid flow or otherwise interfere with one or both of the first and second affinity binding reactions.

Prior devices have attempted to enhance sensitivity or specificity by pretreating various parts of the device with reaction or flow enhancing reagents, pH conditioning chemicals, or even non-specific adhesive blocking molecules which will "block-out" non-analyte molecules which might cause non-specific adhesion, or otherwise compete with the analyte in question for specific binding members, especially in the reaction zones region of the strip. These attempts have met with limited success in some types of testing, but do not provide the desired accuracy in many others. .Also, pretreatment with two or more of the above pretreatments exacerbates the difficulties in obtaining uniform manufacturing due to potential incompatibilities between the pretreatment chemicals. For example, the pH conditioner might disrupt the effectiveness of the non-specific blocking member molecules. Or, the manufacturing step of pretreating with the second pretreatment chemical can dislodge some of the first pretreatment chemical.

Further, lot-to-lot variation in the manufacture of many IVD test devices can often lead to ambiguous results, such as false negatives as well as weak false positives, so-called "ghost lines" or "phantom lines". False negatives typically occur when nonspecific molecules interfere with the first and/or second affinity binding actions. It has been found that non-analyte molecules can clump together in liquid samples that are not well mixed so that they temporarily prevent access between analytes and binding members. Even temporary interference in past devices can prevent an adequate number of labeled analyte complexes and/or ultimately immuno-sandwich complexes from forming. In this way, if a non-analyte molecule or clump of molecules blocks access between analytes and binding members for only a few seconds, it may be enough to induce a false negative result. Further, clumps of non-analyte molecules can carry an overabundance of the labeled mobilizable binding members to the second affinity binding site to generate a false positive result.

One area of recent improvement in rapid diagnostic testing involves using the capabi lities offered by mobi le communication devices such as smart phones. As disclosed in Ozcan et al., U.S. Pat. No. 8,916,390, incorporated herein by reference, a lateral flow-type strip can be automatedly scanned by the camera of a smart phone which can be interpreted by software to obtain a result and deliver it to a wireless network. Lateral flow devices are useful due to their low cost and ease of use. However, prior lateral flow devices suffer from low accuracy as detailed above. This is especially true for saliva testing because of the low concentrations of analytes present. Current lateral flow strips cannot provide the necessary sensitivity and specificity within the time normally allotted to a typical law enforcement action such as a traffic stop.

The low accuracy can be due to a number of problems unique to lateral flow- type tests. First, there is often uneven movement of the immunoparticles within the nitrocellulose membrane. Smaller, non-analyte molecules mixed together with the larger analyte molecules and compete for sites and often prevent the larger molecules from reacting in the desired fashion .

Moreover, sometimes a testing result can fail because users are color blind and cannot read the color of the test and control lines on the test strip correctly.

Therefore, there is a need to improve the accuracy of rapid 1VD test devices and methods for reading such test devices so that rapid inexpensive easily conducted quantitative immunological testing becomes a reality.

SUMMARY OF THE INVENTION

Embodiments of the present invention further provide a device for testing a liquid sample for the concentration of at least one analyte comprising a test device comprising a plurality of channels each configured to receive a test strip therein; a front side housing covering a front side of each of the plurality of channel s; a back side housing covering a back side of each of the plurality of channels; and an opening formed by configuring a first length of the front side housing less than a second length of the back side housing, the opening providing fluid access to a whole side of a sample pad of the test strip when the test strip is inserted into one of the plurality of channels.

Embodiments of the present invention provide a system for testing a liquid sample for the concentration of at least one analyte comprising a test strip comprising a sample pad for receiving a sample, a conjugate pad containing nanoparticle conjugate, a test line for indicating a test result, and a control line for indicating the test result; and a test device comprising a plurality of channels each receiving the test strip therein, a front side housing covering a front side of each of the plurality of channels, a back side housing covering a back side of each of the plurality of channels, and an opening formed by configuring a first length of the front side housing less than a second length of the back side housing, the opening providing fluid access to a whole side of a sample pad of the test strip.

Embodiments of the present invention also provide a system for testing a liquid sample for the concentration of at least one analyte comprising a test strip comprising a sample pad for receiving a sample, a conjugate pad containing nanoparticle conjugate, a test line for indicating a test result, and a control line for indicating the test result; and a flexible test device comprising a plurality of channels each receiving the test strip therein, a front side housing covering a front side of each of the plurality of channels, a back side housing, integral with the front side housing and joined to the back side housing via side members, covering a back side of each of the plurality of channels, an opening formed by configuring a first length of the front side housing less than a second length of the back side housing, the opening providing fluid access to a whole side of a sample pad of the test strip, and a compression pad formed in the back side of each of the plurality of channels, the compressing pad forming a region of reduced height inside each of the plurality of channels, the region positioned at a location of a conjugate pad of the test strip when the test strip is inserted into one of the plurality of channels. These and other features, aspects and advantages of die present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the present invention are illustrated as an example and are not limited by the figures of the accompanying drawings, in which like references may indicate similar elements.

FIG. 1 is a perspective view of a driven flow test cartridge according to an exemplary embodiment of the present invention;

FIG. 2 is a side cross-sectional view of a test strip used in the test cartridge of

FIG. 1;

FIG. 3 is a side view of the test cartridge of FIG. 1, illustrating an excessive specimen reservoir, according to an exemplary embodiment of the present invention;

FIG. 4 is a detailed side cross-sectional view of the test cartridge of FIG. 1, illustrating photosensitive sensors used to detect light reflecting from the test line and the control line of the test strip;

FIG. 5 is a schematic representation of the test cartridge of FIG. 1 , inserted into an electronic reading device, where the reading device sends a wireless signal to a handheld computing device, according to an exemplary embodiment of the present invention;

FIG. 6 is a circuit diagram illustrating an exemplary shunt regulator to provide a constant stabilized voltage to the lamps of the electronic reading device;

FIG. 7 is a graph showing how the shunt regulator of FIG. 6 provides a constant stabilized voltage;

FIG. 8 is a schematic representation of the components of the electronic reading device;

FIG. 9 is a graph showing two concentrations of sample run on the driven flow test cartridge of FIG. 1 and read on the electronic reading device,

FIG. 10 is a plan view of a top component of the test cartridge of FIG. 1;

FIG. 11 is a plan view of the base component of the test cartridge of FIG. 1;

FIG. 12A is a cross-sectional view of a cap fitting on the test cartridge of FIG. 1;

FIG. 12B is a top view of the cap fitting on the test cartridge of FIG. 1;

FIG. 13A is an exploded view of the test cartridge of FIG. 1 ;

FIG. 13B is a plan view of the test cartridge of FIG. 1 fully assembled;

FIG. 14A is a top view of a base housing of an electronic reading device;

FIG. 14B is a bottom view of the base housing of the electronic reading device; FIG. 15A is a top view of a top housing of die electronic reading device;

FIG. 15B is a bottom view of the top housing of the electronic reading device; FIG. 16 is a top view of a light mask used in the electronic reading device, FIG. 17 is a perspective view of a trigger head receiver used in the electronic reading device;

FIG. 18 is a side view of a printed circuit board used in the electronic reading device;

FIG. 19 is a top view of the trigger head receiver of FIG. 17 assembled with the light mask of FIG 16;

FIG. 20 is a perspective view of the assembly of FIG. 19 assembled into the base housing of FIGS. 14A and 14B;

FIG. 21 is a perspective view of the assembly of FIG. 20 assembled with the printed circuit board of FIG. 18;

FIG. 22 is a perspective view of the assembly of FIG. 21 assembled with the top housing of FIGS. 15 A and 15B;

FIG. 23 is a perspective view of the test cartridge of FIG. 1 assembled with the electronic reading device of FIG. 22,

FIG. 24 is a front view of a test strip retention assembly according to an exemplary embodiment of the present invention;

FIG. 25 is a back view of the test strip retention assembly of FIG 24;

FIG 26 is an insertion end view of the test strip retention assembly of FIG. 24; FIG. 27 is a cross-sectional view of the test strip retention assembly of FIG. 24, illustrating the insertion of a test strip therein; and

FIG. 28 is a detailed cross-sectional view of the test strip retention assembly of FIG. 24 with a test strip inserted therein.

Unless otherwise indicated illustrations in the figures are not necessarily drawn to scale.

The invention and its various embodiments can now be better understood by turning to the following detailed description wherein illustrated embodiments are described. It is to be expressly understood that the illustrated embodiments are set forth as examples and not by way of limitations on the invention as ultimately defined in the claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS AND BEST

MODE OF INVENTION

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in die art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such

combinations are entirely within the scope of the invention and the claims.

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details. The present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiments illustrated by the figures or description below.

As is well known to those skilled in the art, many careful considerations and compromises typically must be made when designing for the optimal configuration of a commercial implementation of any system, and in particular, the embodiments of the present invention. A commercial implementation in accordance with the spirit and teachings of the present invention may be configured according to the needs of the particular application, whereby any aspects), feature(s), function(s), result(s), components), approach(es), or step(s) of the teachings related to any described embodiment of the present invention may be suitably omitted, included, adapted, mixed and matched, or improved and/or optimized by those skilled in the art, using their average skills and known techniques, to achieve the desired implementation that addresses the needs of the particular application.

Broadly, embodiments of the present invention provide a test device that can use driven flow technology in a simplified testing format, such as dip format, to provide a rapid diagnostic test device that shortens the interpretation time of the test result to less than one minute and minimizes manufacturing costs. As described in U.S. Patent No. 9,535,061, the contents of which are herein incoiporated by reference, driven flow forces can come from squeezing the sample pad and compressing the conjugate pad. The present invention shortens the distance between the opening provided on the front side housing of the test device and the conjugate pad without squeezing the sample pad and without requiring a separate component, such as a cap, to squeeze the sample pad. The test device of the present invention can utilize a single, integral housing made from, for example, a flexible transparent material, such as polyethylene terephthalate (PET) that integrates the traditional base and top, or inner and outer tubes, into one to save the manufacturing costs. The flexible housing used in the testing device of the present invention not only provides a planar format, but also can be flexed to provide an arc or even a peripheral format when the test strip number in a dip format is too many (e.g., more than six) to cause uneven dipping samples.

The three-sided close housing can efficiently prevent the overflowing sampling problem. In a traditional dip format, the strip has limited dip depth which should be lower than the conjugate pad position. In the present invention, there is no limitation about the sampling depth of die test strip. The testing device can be floated or inserted in any container with specimen, even midstream in the specimen.

As discussed below, an electronic reader may be used with any of the test devices described herein. Typically, a planar format is preferred to provide a flat plane for easily receiving incident light or for taking images for electronic processing as a final testing result on a digital display. The test device of the present invention, being flexible, can be positioned in a flat plane, even if the dip test is performed with the test device cuived in an arc.

Referring to FIGS. 1 through 3, a sample stream 12 may be received onto a sample pad 14 of a test strip 24 positioned in a test cartridge 10. In some embodiments, a sample may be delivered by pipette, or some other fluid transfer device, to the sample well 22, formed as a hole in the top component 20 of the test cartridge 10. When the sample is from the sample stream 12, a portion of a base component 16 of the cartridge 10 may act as a refracting pad 86 (see FIG. 1 1) to refract the sample stream 12 vector partially along the sample pad as shown by arrow 26.

FIG. 2 shows a detailed view of the test strip with a portion of the top component 20 removed. The test strip can include the sample pad 14 that can deliver sample to a conjugate pad 18 containing nanoparticles conjugate 30 therein.

Compression bars 28 of the top component 20 can create a limited flow channel through which sample may pass along the test strip. The sample and nanoparticles conjugate 30 may pass onto the nitrocellulose membrane 38 of the test strip and interact with a test line 32 and a control line 34. The test line 32 and control line 34 may be read by eye or by an electronic reading device 62 (see FIG. 5), as described in greater detail below. An absorbent pad 40 may be disposed on a distal end of the test strip.

As shown in FIG. 3, die sample pad 14 may be disposed over a reservoir 42 formed on the base component 16. During running tests by the stream method, most concern to cause test failure is so called "flooding" which applies excessive amounts of sample through the conjugate pad 18. In the present invention, the collimated compression bars 28 stop the flooding sample by restricting the top and bottom surface of the conjugate pad 18, thus most of the flooding sample will be retained on the reservoir 42 located before the conjugate pad 18. Thus, the conjugate pad 18 is sandwiched at an appropriate pressure between the compression bars 28 and the surface of the base 16. Such an appropriate pressure helps releasing specific labeled molecules, such as the nanoparticle conjugate 30 under the stream force.

Referring now to FIGS. 4 and 5, two incident light paths 48 emitted from two individual light-emitting diodes (LEDs) 50 can be aligned and collimated at the test line 32 and the control line 34. A test line photosensitive sensor 44 and a control line photosensitive sensor 54 may be located beside each LED 50 to receive the reflecting lights 46, 52 from the test line 32 and the control line 34, respectively. The electronic signals from the sensors 44, 54 can be transmitted to a microprocessor 56 for further data processing. In some embodiments, the electronic reading device 62, with the inserted test cartridge 64 may be configured to send a wireless signal 60, via a wireless protocol, such as Bluetooth, to a computing device 58, such as a tablet computer, smart phone or the like. The computing device 58 may be configured to provide output data, such as test results, quantitative analysis, or the like, to the user.

In some embodiments, as discussed in greater detail below, when the inserted test cartridge 64 is inserted into the electronic reading device 62, the performance of the test cartridge analysis can proceed without requiring the user to push any buttons. The computing device 58, once it receives the data via the wireless signal 60 from the microprocessor 56, can include software to process the test data as desired. The software may further provide for traceability of test results by inputting user information such as user name, patient ID, or the like, and the test results may be saved on the computing device or on connected external storage.

Referring now to FIGS. 6 and 7, a shunt regulator circuit is shown in FIG 6 that is capable of providing a constant stabilized voltage. LED1 and LED2 are surface mount LED lamps and RD indicates a photosensitive sensor. The graph of FIG. 7 is based on the Table 1 below, where V-ADC 1 (MV) and VCC (MV) are represented on the graph, where V-ADC 1 is the output voltage while VCC is the input voltage. As can be seen, fluctuations in input voltage with the shunt regulator circuit results in little if any change in voltage.

In the present invention, in order to increase the repeatability and precision of the digital test result, a constant stabilized voltage to the LED 50 is incorporated. Some digital devices, such as those in U.S. Patent Numbers 8,828,329; 9,453,850; 9,588,113; and 7,220,597 and U.S. Patent Publication No. 2013/0040401, adapt the disposable button cell battery to supply the LED. However, the low capacity of cell batteries cannot provide stabilized voltage during the testing because voltage discharges or battery voltage attenuates from time to time. Therefore, there can be no guarantee the device will work properly due to the lack of stabilized power control.

Referring to FIG. 8, in order to improve this issue, a 3.6V, 40mA rechargeable battery 78, as part of rechargeable battery module 74, coupled with a constant stabilized voltage and light source module 76, which can incorporate a shunt regulator, such as TL431 S, from Texas Instruments, can provide constant stabilized voltage at 2.8 V, which is optimal for the working voltage range of 2.7 - 2.8 V of the surface mount LEDs. Once the voltage is below 2.8V, a message can be provided to the user on their computing device 58 to remind the user to recharge die electronic device by using an appropriate charging cord. The 3.6V battery also provides the power for the wireless transmission, such as a Bluetooth module 68. In order to improve the accuracy of the test result, the electronic reading device 62 can include a color recognition sensor detecting module 72 that receives signals from the photosensitive sensors 44, 54 (referred generally as photosensitive sensor module 70 in FIG. 8) and RGB individual vectors and then outputs a signal to the microprocessor 56 in which they are compared with a build-in database. The final output signals from the microprocessor 56 can be transmitted by Bluetooth module 68 to the computing device 58 for display to the user.

Referring now to FIG. 9, the test performance of the cartridge and electronic reading device are described. In this analysis, hCG strips with 25 mR7/mL cutoff value are used for running a test with the following steps. First, one strip is assembled into the cartridge. Next, one drop (about 45 μί) of 5 or 600mnJ/mL standard control (as confirmed by GC/MS) is added into the sampling well 22. The cap is immediately placed on the cartridge. The cartridge is then placed in to the electronic reading device 62. The intensities of the test line and the control lines are measured over time and the values are expressed in FIG. 9.

Through the electronic reading device, the intensities of the test line and the control line is measured every second. From the two test line intensities of FIG. 9, the driven flow effect to drive specific molecular binding with antigen on the membrane was completed after 22 seconds and were stabilized through one minute with very subtle variation. From the two control line intensities of FIG. 9, they developed around 15 seconds later than the test line because of the lagging migration time behind the test line. The intensities of the control line become stable after 33 seconds and last until one minute.

The feasibility of quantitative analysis is observed by the intensity gap of the test lines between the 5 mlU/'mL and the 600 mlU/mL concentrations. A significant intensity gap was noted of around 93 based on electron-magnified scale which is more reliable and precise than vision interpretation. This makes the test result become quantitative based on the intake human chorionic gonadotropin detected concentration versus electron-magnified signals.

An accuracy, repeatability and precision validation of the digital driven flow cartridge of the present invention was conducted. In this validation, two sampling methods, "stream fluid" and "dropped fluid" are involved with negative, 5tnIU/mL and 600 mlU/mL control specimens, respectively. Each 10 strips from three different lots of hCG strips were assembled in cartridges. Each test was run by experienced technicians and the results were recorded with "negative", "positive" or "invalid" and an electron- magnified signal was observed at 1 minute.

In the "stream fluid" method, 20 mL of specimen is poured gradually at 45 degrees on the opening end of the cartridge, as shown in FIG. 1. After finishing the sampling, the cartridge is inserted into the electronic reading device 62 and the testing is initiated.

In the "dropped fluid" method, one droplet (about 45 μ[,) of specimen is dropped on the sampling well 22 of the cartridge of FIG. 1. After finishing the sampling, the cartridge is inserted into the electronic device 62 and the testing in initiated.

The table below summaries the validation test results.

From all 180 tests results above, they show the digital driven flow cartridge complies 100% in accuracy, repeatability and precision under three hCG concentration levels of negative, 5mIU/mL and 600 mIU/mL.

Referring now to FIGS. 10 through 13B, the components of the test cartridge 10 are shown in greater detail. FIG. 10 shows the top component 20 with a single reading window 80, one sampling well 22 and five compression bars 28. FIG. 11 shows die base component 16, illustrating the refracting pad for sampling 86, reservoir 42, compression cushion 84 which acts opposite the compression bars 28 of the top component 20 and a trigger head 82. The trigger head 82, as discussed below, can turn on the light source and start the testing when die cartridge is inserted into the electronic reading device. FIGS. 12A and 12B show the cap 90 that fits over the end of the cartridge and covers the exposed sample pad of the testing strip. The cap 90 can include a compression ramp 88 to modulate the pressure of the compression bars 28 to the conjugate pad 18. The cartridge 10 may be assembled as shown in FIGS. 13A and 13B, inclusive of the test strip 24.

Referring now to FIGS. 14 through 22, the components of the electronic reading device 62 are shown in greater detail. In FIGS. 14A and 14B, the bottom housing 94 is shown. The top housing 96 of FIGS. 15A and 15B may onto the bottom housing 94. A power light hole 98 may be formed in the top housing 96 to allow a user to see a lamp indicating that the electronic reading device 62 is powered on. FIG. 16 illustrates a light mask 108 having an opening 100 for a light switch and an LED light window 102. The light mask 108 can keep the light emitting and reflecting in a dark background. FIG. 17 shows the trigger head receiver 104. The trigger head 82 of the cartridge 10 may fit into an opening 106 of the trigger head receiver 104 to turn on the electronic reading device and begin the testing procedure.

FIG. 18 shows a printed circuit board 110 that controls the electronic reading device 62. The printed circuit board can include three LED lights 122, a light switch 120, a microprocessor 56, a port 112, such as a micro USB port, a power light 104 and a rechargeable battery 78.

As shown in FIG. 19, to assemble the electronic reading device 62, a user can place the trigger head receiver 104 into the light mask 108. Next, as shown in FIG. 20, the assembly of FIG. 19 can be placed into the base housing 94. The printed circuit board 110 may then be placed on the top of the light mask 108 as shown in FIG. 21, and the top housing 96 may then be placed on the bottom housing 94 to create the electronic reading devi ce 62.

FIG. 23 shows the electronic reading device 62 in use with a cartridge 10 inserted therein. The dual sampling method in a single cartridge, as provided by embodiments of the present invention, provides at least two choices for sampling for point-of-care (POC) and over-the-counter (OTC) testing. The cartridge, being made with specially designed compression bars and a refracting pad that converts a stream force into a driven flow force by refracting/pressing/squeezing/leading the stream to the reaction area that elutes and releases nanoparticle conjugate completely from the conjugate pad to the reaction zone. The testing time with the cartridge of the present invention is between about 30 seconds to about 1 minute, which is about 10 times faster than traditional lateral flow devices, which typically take from about 5 minutes to about 10 minutes.

The digital device of the present invention includes the progressive compression driven flow cartridge integrated with an electronic reading device which makes the reading of the result fast, easy and accurate. The digital texture format in this device provides quantitative concentration of analytes, for example, the concentration of intake human chorionic gonadotropin, which may be detected from about 5 to about 600 mlU/mL. The device of the present invention significantly increases the accuracy in interpreting the test result versus vision interpretation.

Referring now to FIGS. 24 through 28, a test strip retention assembly 240, or simply, testing device 240, can include a plurality of channels 242 for retaining a test strip 270 therein. While 17 channels 242 are shown in FIGS. 24 and 25, the number of channels 242 may include any suitable number of channels, depending on the particular application. A front side housing 248 of each channel 242 can extend a length of the channel 242 that is less than a back side housing 250 of the channel, providing an opening 244 visible from a front view, as shown in FIG. 24, of the test strip retention assembly 240. Side members of each channel can join the front side housing 248 and the back side housing 250. The opening 244 may be suitable for receiving a specimen 284, as shown in FIG. 28 and discussed in greater detail below.

The test strip(s) may be inserted into the channels 242 in the direction indicated by arrow 246 in FIG. 25. Once inserted, as shown in FIG. 28, a sample pad 282 of the test strip 270 may receive the specimen 284 by various methods, such as a drop or stream, as indicated by arrow 286, or via a dip method by dipping the test strip retention assembly 240 into a sample containing the specimen 284. As discussed in greater detail below, a conjugate pad 280, having gold colloid 278, for example, may be disposed under the front side housing 248 so that the specimen 284 does not overflow by capillary force through the conjugate pad 280 when specimen 284 is either over-dosing or fast-dosing to flood off the gold colloid 278. A compression pad 290 may provide a raised floor of the back side housing 250 to press the conjugate pad 280 and gold colloid 278 against the front side housing 248, thus providing a driven flow of the specimen 284 along die test strip 270 toward the absorbent pad 288 end thereof. The compression pad 290 may be formed in various manners. For example, the compression pad 290 may be formed from raising the back side housing 250 as shown in FIGS. 27 and 28, or may be formed by making the region of the compression pad 290 thicker. Regardless of manufacture design, the compression pad 290 provides a raised region, raised toward the front side housing 248, at the area of the conjugate pad 280 when the test strip 270 is inserted into the testing device 240.

The test strip 270, like the test strip 24 described above, can include antigen on a test line 276 and a control line 274 disposed on a nitrocellulose membrane 272.

The specimen 284 can be introduced from the opening 244 formed from the shortened length of the front side housing 248 (as compared to the length of the back side housing 250). The opening 244 is close to the conjugate pad 280 of the test strip 270. In other words, the front side housing 248 terminates just beyond the location of the conjugate pad 280, while the back side housing 250 typically terminates at the sample pad 282 of the test strip 270. Typically, the distance (where distance here refers to linear distance along an axis of the test strip 270) of the opening 244 to the conjugate pad 280 is about 1.0 - 5.0 mm, typically less than 5 mm, even more typically 2 mm or less. However, the distance of the opening 244 to the conjugate pad 280 is not below lmm, as flooding of the gold colloid 278 can occur.

An experiment was conducted where the distance between the opening 244 and the conjugate pad 280 was varied and the time it took was measured for a sample of four droplets of specimen, introduced to the sample pad 282, to flow out of the conjugate pad 280. The results of this experiment are summarized on die table below. As can be seen in the table below, if the position of the opening 244 is close to the conjugate pad, the driven flow force from compression can achieve the interpretation time typically less than 1 minute.

All the features disclosed in this specification, including any accompanying abstract and drawings, may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

Claim elements and steps herein may have been numbered and/or lettered solely as an aid in readability and understanding. Any such numbering and lettering in itself is not intended to and should not be taken to indicate the ordering of elements and/or steps in the claims.

Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiments have been set forth only for the purposes of examples and that they should not be taken as limiting the invention as defined by the following claims. For example, notwithstanding the fact that the elements of a claim are set forth below in a certain combination, it must be expressly understood that the invention includes other combinations of fewer, more or different ones of the disclosed elements. Insubstantial changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalently within the scope of the claims. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements.

The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted and also what incorporates the essential idea of the invention.