Quick Review Cards for Medical Laboratory Science

Qualitative Platelet Disorders Hematology Review 343

DISORDER EXPLANATION LABORATORY TESTS

Inherited

Bernard-Soulier syndrome

Glanzmann’s thrombasthenia

d-storage pool disorder

Acquired

All can result in serious bleeding.
VWF = Von Willebrand factor.

Lack of functional glycoprotein (GP) Ib/IX/V on

plt surface prevents interaction with VWF.

Abnormal plt adhesion to collagen.

Deficiency or abnormality of plt membrane GP

IIb/IIIa. Fibrinogen can’t attach to plt surface &

initiate plt aggregation.

Dense granule deficiency. Lack of ADP release.

Functional plt disorders occur with chronic

renal failure, myeloproliferative disorders, car-

diopulmonary bypass, use of aspirin & other

drugs. Mechanisms vary.

Giant plts with dense granulation. ↑closure

time (PFA). Abnormal aggregation with

ristocetin.

↑closure time (PFA). Abnormal aggregation

with ADP, collagen, epinephrine.

Abnormal secondary aggregation with ADP &

epinephrine.

Abnormal plt aggregation.