Platelet function analyzer

Device utilized to evaluate platelet function.

Platelet function analyzer (PFA-100, Dade Behring, Inc, Deerfield, Ill).

A high shear system that challenges platelets, in anticoagulated whole blood, to occlude an aperture cut into a membrane coated with collagen and an agonist epinephrine or adenosine 5′-diphosphate, ADP.

Results are expressed in seconds, with a maximum test time of 300 seconds.

Blood is drawn into a thin glass tube covered with collagen and with either epinephrine or ADP.

The glass coating activates platelets in the moving sample and promotes adherence and aggregation of the platelets.

The time it takes for a clot to form inside the glass tube is ref2242ed to as the closure time.

The initial analysis is done with collagen/epinephrine (EPI).

If the initial closure time with collagen/epinephrine is normal it is likely that platelet dysfunction does not exist.

If the closure time is abnormal with the collagen/epinephrine test the test with collagen/ADP is run and an abnormal result indicates the presence of a platelet dysfunction requiring testing for an inherited or acquired bleeding disorder.

If the collagen/ADP evaluation is normal the abnormal collagen/EPI test may reflect aspirin exposure.

A single dose of aspirin can impair the collagen/EPI result for about 10 days duration.

Sensitive to a variety of platelet and von Willebrand factor defects (inherited, acquired, or drug-induced), as well as hemorheologic factors.

Not an accurate predictor of the likelihood of a patient bleeding excessively at surgery.

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