PURPOSE: To measure the agglutination power of blood platelet in a short time with good accuracy by adding a constant amount of PRP to an agglutination inducing agent of stepwise varied amounts, and determining the minimum amount of the inducing agent at which agglutination is observed.

CONSTITUTION: Fourty pieces of recesses 2 are provided to a plastic plate 1 sizing 8cm×10cm, and an aqueous suspension of collagen is injected into these recesses 2 in such a manner that collagen is contained at 0, 4, 2, 1, 0.5, 0.25, 0.125, 0μg respectively for numbers 1W8, and is freeze-dried, whereby a kit for measuring the agglutination power of blood platelet is produced. A sample PRP is injected by each 100μl into each of these recesses 2, and after it is stirred for 5min with a micromixer, the presence or absence of agglutination is observed by naked eyes, whereby the results are obtained in a short time.