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Platelet Associated Antibodies, Direct Assay
0095614
Ordering Recommendation

Support the diagnosis of autoimmune thrombocytopenia (AITP).

Mnemonic
PAIG
Methodology
Qualitative Flow Cytometry
Performed
Sun-Sat
Reported
2-3 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Lavender (EDTA) or pink (K2EDTA). 
Specimen Preparation
Transport 4 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
CRITICAL ROOM TEMPERATURE. 
Unacceptable Conditions
Clotted, hemolyzed, frozen, or refrigerated specimens. Specimens older than 48 hours. 
Remarks
Specimens must be analyzed within 48 hours of collection. Required amount of blood may be dependent on platelet count. 
Stability
Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable 
Reference Interval
IgG: Negative
IgM: Negative
Interpretive Data
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.

Compliance Statement A: Analyte specific reagents (ASR) are used in many laboratory tests necessary for standard medical care and generally do not require U.S. Food and Drug Administration (FDA) approval or clearance. This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. This test should not be regarded as investigational or for research use.

Note
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).
Components
Component Test Code*Component Chart NameLOINC
0095612Platelet Antibodies Direct, IgG29497-5
0095613Platelet Antibodies Direct, IgM29498-3
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Direct Platelet Antibody
  • Anti-Platelet Antibodies
  • Cell-Bound Platelet Antibody Test
  • Platelet Associated Immunoglobulins (IgG & IgM)