Dependent Platelet Agglutination

This test requires platelet-rich plasma from a patient recovering from a drug-induced platelet lysis. Various concentrations of the suspected drug have to be used and the mixture incubated in the presence of the patient s serum. Platelet agglutination is best determined on a siliconized slide, using a phase contrast microscope. An indirect method using platelets from a normal donor can also be adapted. It is, however, less sensitive and reliable (Dausset et al. 1964). 

They are several limiting factors to the application of this technique, such as  

The specific antibody is often detectable in the serum for only a short period of time 

The preparation of a platelet-rich plasma is a delicate operation spontaneous agglutination often occurs 

Nonimmunologic agglutination of platelets following incubation with some drugs can occur 

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Scott IP, Montgomery RR, Retzinger GS. Dimeric ristocetin flocculates proteins, binds to platdets, and mediates von-Willebrand factor-dependent agglutination of platelets. JBiol Chem 1991 266 8149-8155. 

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