 |
 |
 |
 |
Does anyone have a good Anti-platelet IgG assay they are using?
How about Reticulated platelets. We have been using protocols
published by Kinder te al Arch Pathol Lab Med v117 1993 for
Reticulated platelets and are not entirely satisfied with
the very dim fluorescence. Any takers?
To: cyto-inbox
From: H. Rinder/Kinder/Binder (pick one)
When we do our monthly QA/QC for reticulated platelets, we label washed
platelets with FITC-anti-GPIIb/IIIa and adjust the FL1 PMT for a signal in
the 2nd to 3rd decade. We then use that PMT setting for measuring thiazole
orange fluorescence for reticulated platelets; this usually gives an
adequate FL1 signal such that normal controls have between 3% - 7%
reticulated platelets. We use the method by Bonan and Rinder in Cytometry
14:690-4, 1993 to set our threshold for reticulated platelet quantitation.
Alternatively, you can use the quantitation methods of Ault and Rinder in Am
J Clin Path 98:637-46, 1992. However, both methods use a similar PMT
adjustment as above for getting an adequate signal.
Regarding anti-platelet IgG, it sounds like we have a similar frustration
level. We consistently find that PAIgG is sensitive but poorly specific for
immune-mediated thrombocytopenia. We have only done direct PAIgG by flow and
are currently exploring using an indirect flow-based method, but I am not
optimistic for the reasons that Ken Ault and others have summarized. When
there is increased platelet destruction (regardless of the mechanism),
platelet-associated IgG is increased, and this is usually reflected in the
serum anti-platelet IgG. We do the test but report it with numerous caveats.
Good luck.
Harv Rinder
henry.rinder@yale.edu
Ph 203-737-2088
Fx 203-737-4111
|
|
|
|