We consider manual counts as less quick but more precize than authomatic (electronic) since in the latter case the counts are based on the size of particles, so everything that has the same size as platelet will be counted as an event. Anyway both give comparable results- thrombocytopenic probe in comparison with normal one remains thrombocytopenic no matter what type of counts performed. In our lab we use as a routine procedure manual counts and sometimes we use automatic cell counter in addition.
 

PROTOCOL

1. Obtain blood from plexus retroorbitalis by using sliconized microcapillaries (20ul)
   
2. Immediately dilute 1:100 in Unopette kits (Becton Dickinson)
3. Let the probe stay for 1.5 hrs RT for complete erythrocyte lysis
4. Count platelets under a phase contrast microscope at x400 magnification using Neubauer hemocytometer
   

SOLUTIONS

The Unopette Reservoir contains 1.98ml of diluent mixture: Ammonium oxalate 11.45gm, Sorensen`s phosphate buffer 1.0gm , Thimerosal 0.1gm, Purified water qs to 1L  

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