Platelet Associated Antibodies, Direct Assay
Support the diagnosis of autoimmune thrombocytopenia (AITP).
New York DOH Approval Status
Lavender (EDTA) or pink (K2EDTA).
Transport 4 mL whole blood. (Min: 1 mL)
CRITICAL ROOM TEMPERATURE.
Clotted, hemolyzed, frozen, or refrigerated specimens. Specimens older than 48 hours.
Specimens must be analyzed within 48 hours of collection. Required amount of blood may be dependent on platelet count.
Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Qualitative Flow Cytometry
Negative (IgG & IgM): No excess antibodies were associated with the patient's platelets. An immune cause of thrombocytopenia is unlikely.
Positive (IgG and/or IgM): An increase in platelet associated immunoglobulin is noted. An immune cause of thrombocytopenia should be considered. However, many conditions can result in an increase in platelet associated antibodies; for example, IgM rheumatoid factor antibodies.
Strong Positive (IgG and/or IgM): A definite increase in platelet associated immunoglobulin is noted and an immune cause of thrombocytopenia should be considered. However, many conditions can result in an increase in platelet associated antibodies; for example, IgM rheumatoid factor antibodies.
This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.
Laboratory Developed Test (LDT)
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. Refer to Platelet Antibodies, Indirect (ARUP test code 0051050).
|Component Test Code*||Component Chart Name||LOINC|
|0095612||Platelet Antibodies Direct, IgG||29497-5|
|0095613||Platelet Antibodies Direct, IgM||29498-3|
- Direct Platelet Antibody
- Anti-Platelet Antibodies
- Cell-Bound Platelet Antibody Test
- Platelet Associated Immunoglobulins (IgG & IgM)