Platelet Autoantibody Test (Sendout)

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General Information

Lab Name
Platelet Autoantibody Test (Sendout)
Lab Code
RPAA
Epic Name
Platelet Autoantibody Test (Sendout)
External Test Id
3640-00
Description

Test Information: Idiopathic Thrombocytopenic Purpura (ITP) is a diagnosis associated with elevated platelet associated IgG, IgM or both. Positive autoantibody test results are indicative of autoimmune destruction. Positive indirect antibody test results, using patient’s plasma against normal random platelets, may indicate ITP depending upon the patient’s transfusion or pregnancy history. In approximately 85% of patients with ITP, the presence of an autoantibody can be detected.

    Additional Test Information: Patients who require autoantibody testing must be platelet transfusion independent for approximately 5 days to ensure that the platelets being tested are the patient’s own platelets and not circulating donor platelets.

    Forms & Requisitions
    Synonyms
    3640-00, Idiopathic Thrombocytopenic Purpura, ITP Workup, Platelet Flow Cytometry
    Components
    Code Name
    RPAAR Platelet Autoantibody Result
    S2PAA Platelet Autoantibody Testing Lab

    Interpretation

    Method

    Flow Cytometry

    Reference Range
    See individual components

    Ordering & Collection

    Specimen Type
    Blood
    Collection

    Collection Timing:

    • Collect Monday through Thursday to ensure delivery within the 24-hour stability limit.
    • Samples collected on Fridays must be received by Bloodworks Northwest Platelet Immunology lab by 10:00am.
    • Avoid collections on weekends and on/before holidays.

    Collection: 5 mL blood in BLUE TOP (Citrate) AND appropriate amount of blood in LAVENDER TOP tube based on platelet count, see below.

    • Platelet Count: >= 50,000, Collect: 2 x 10 mL EDTA/LAVENDER tubes
    • Platelet Count: 20,000 to 49,999, Collect: 3 x 10 mL EDTA/LAVENDER tubes
    • Platelet Count: 10,000 to 20,000, Collect: 4 x 10 mL EDTA/LAVENDER tubes
    • Platelet Count: Less than 10,000, Collect: DO NOT DRAW***
      • ***Cannot recover sufficient platelets to perform a direct assay of antibody bound to autologous platelets. Contact Lab Supervisor for testing options at (206) 689-6542.
    Forms & Requisitions
    Handling Instructions

    Outside Laboratories:

    • Maintain and transport whole blood samples at ambient temperature.
    • Expedite transport to the laboratory. Samples must be received in the Platelet Immunology Lab within 24 hours of collection.

    Note: Samples received in the Platelet Immunology Lab after 10:00 am on Friday or over the weekend will be cancelled.

    Quantity
    Requested: Refer to collection information.
    Minimum: Refer to collection information.

    Processing

    Receiving Instructions

    Store and transport samples at ambient temperature. Expedite transport due to 24-hour stability limit.

    Sendouts (UW-MT/HMC) and FHCC SPS:

    • Bloodworks NW Test: 3640-00
    • Interfaced: No
    • Send sample(s) with a copy of the Bloodworks Northwest HLA Requisition or the EPIC requisition (must indicate the test or panel to be ordered at Bloodworks NW).
      • Package sample(s) with the associated requisition in a biohazard bag (one patient per bag). Orders received with multiple patient samples/requisitions in the same biohazard bag will be rejected by Bloodworks NW.
    • Samples must be received by BloodWorks NW Platelet Immunology lab within 24 hours of collection.
    • Samples sent on Friday must be received in lab by 10:00 am.

    Stability: Ambient (required): 24 hours.

    Misc Sendout

    Performance

    Lab Department
    Sendouts(SO)
    Frequency
    Performed: Monday - Friday morning. TAT: 1 business day.
    Available STAT?
    No
    Performing Location(s)
    Sendout Bloodworks Northwest Platelet Immunology/Genomics Laboratory (Central HPG)

    921 Terry Ave
    6th Floor - SDL
    Seattle, WA 98104

    Genomics Testing Laboratory (for RBC genotyping): (206) 689-6269

    Platelet Immunology Laboratory: (206) 689-6543

    Laboratory staffed for questions Monday through Friday, 08:00 am to 04:30 pm.
    Other Locations/Notes

    Bloodworks Northwest Platelet Immunology Lab: (206) 689-6543

    Billing & Coding

    CPT Codes
    86022, 86023
    LOINC
    30896-5