Test Directory

• Platelet Antibodies Direct, IgG
• Platelet Antibodies Direct, IgM

Support the diagnosis of autoimmune thrombocytopenia (AITP).

Specimen Type: Whole Blood

Collection Container: Lavender Top (EDTA)

Alternate Collection Container: Pink Top (EDTA)

Desired Specimen Volume: 4 mL

Testing requires special attention to specimen collection and shipping in order to ensure the integrity of the sample. Technical Support/Referral Testing must be notified of specimen collection.

1. Collect whole blood in a lavender top (EDTA) tube via venipuncture 8 a.m - 12 p.m Monday - Thursday only.
2. Do not collect two days before a holiday.
3. Fill tube to capacity with whole blood.

1. Transport whole blood in the original collection container.
2. Label tube with a room temperature sticker.
3. Specimens must be analyzed within 48 hours of collection

Transport to the laboratory at room temperature. 

• Hemolysis
• Clotted Specimens

 See patient report.

Detection of platelet-associated IgG and/or IgM may be used to separate thrombocytopenia of immune origin from nonimmune origin. Most patients with ITP have abnormally high levels of IgG associated with their platelets. Occasionally patients will have normal IgG levels but abnormally high levels of IgM. Dual staining and flow cytometric analysis ensures that only platelets are analyzed and relatively small volumes of blood are required. This assay does not distinguish between autoantibodies and alloantibodies, nor does it identify specific types of antiplatelet antibodies, such as those against HPA-1a.