What is the appearance of Glanzmann's thrombasthenia in platelet function testing?

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What is the appearance of Glanzmann's thrombasthenia in platelet function testing?

Glanzmann thrombasthenia is a qualitative defect in platelet aggregation caused by a deficiency or dysfunction of the GPIIb/IIIa receptor, which is essential for crosslinking platelets via fibrinogen. In platelet function testing by aggregometry, platelets from someone with this condition fail to form stable aggregates in response to agonists that rely on GPIIb/IIIa–fibrinogen bridging—such as ADP, epinephrine, collagen, and thrombin—so the aggregation is markedly reduced or incomplete. Ristocetin-induced aggregation, however, remains normal because ristocetin acts through the GPIb–vWF axis rather than through GPIIb/IIIa. Therefore, the appearance is incomplete aggregation with ADP. The other patterns described do not fit GT: normal aggregation with ADP would contradict the GPIIb/IIIa defect; no aggregation with ristocetin suggests a GPIb/vWF problem; and increased aggregation with collagen is inconsistent with a GPIIb/IIIa deficiency.

Glanzmann thrombasthenia is a qualitative defect in platelet aggregation caused by a deficiency or dysfunction of the GPIIb/IIIa receptor, which is essential for crosslinking platelets via fibrinogen. In platelet function testing by aggregometry, platelets from someone with this condition fail to form stable aggregates in response to agonists that rely on GPIIb/IIIa–fibrinogen bridging—such as ADP, epinephrine, collagen, and thrombin—so the aggregation is markedly reduced or incomplete. Ristocetin-induced aggregation, however, remains normal because ristocetin acts through the GPIb–vWF axis rather than through GPIIb/IIIa. Therefore, the appearance is incomplete aggregation with ADP. The other patterns described do not fit GT: normal aggregation with ADP would contradict the GPIIb/IIIa defect; no aggregation with ristocetin suggests a GPIb/vWF problem; and increased aggregation with collagen is inconsistent with a GPIIb/IIIa deficiency.

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