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HIT Antibody PF4-H Reflex (HIT-AB Rflx)

Mnemonic

HIT-AB RFLX

Synonym

Drug Associated Anti-Platelet Antibody - Heparin Associated Thrombocytopenia - HAT - HIT - Heparin Induced Platelet Antibody - Platelet Factor 4

Includes

HIT PF4 Antibody, IgG with reflex to Serotonin Release Assay (SRA)

Guidelines

For a clinical scoring system to assess pretest probability of HIT and other guidance for diagnosing HIT, refer to: Heparin Induced Thrombcytopenia (HIT) Detection and Management Guidelines

Specimen Collection Requirements

Collect

Whole Blood light blue (3.2% Buffered Sodium Citrate) AND Serum, gold (SST) top tubes

Handling

For detailed specimen collection and handling, see Coagulation Specimen Collection Guidelines.

Due to short stability, whole blood specimen tubes must reach the testing department within 4 hours, otherwise submit frozen plasma aliquots. If submitting whole blood, transport at ambient temperature (15-25°C) in original unopened tube. If submitting frozen plasma aliquots and serum aliquots, specimens must remain frozen (-20°C) during transport.

Available 7 days/week. Specimen must be received by 2 pm at Legacy Central Lab for testing to be completed that day.

Preferred Volume

Two 2.7 mL citrated whole blood or two 1.0 mL frozen plasma aliquots, plus 1 SST tube/serum.

Minimum Volume

1.0 mL frozen plasma aliquot, plus 1 SST tube/serum

Transport

Whole Blood: Ambient (15-25°C) 

Plasma and Serum: Frozen (-20°C), aliquots must remain frozen during storage and transport

Rejection Criteria

Refrigerated (2-8°C) whole blood sodium citrate tubes or refrigerated (2-8°C) plasma sodium citrate. 

PLASMA: Clotted samples, samples collected in containers other than 3.2% buffered sodium citrate, tubes filled less than 90%, samples from patients with a Hematocrit greater than 55%, hemolyzed samples due to ex-vivo causes (i.e., difficult draw, poor sample draw), whole blood samples that were frozen before processing.

SERUM: Plasma or other body fluids, severely lipemic, contaminated or severely hemolyzed

Stability

WHOLE BLOOD: Ambient: 4 hours


PLASMA: Ambient: 4 hours; Frozen: (-20°C) 2 weeks, (-70°C) 6 months


SERUM AFTER SEPARATION FROM CELLS: Ambient: 8 hours; Refrigerated: 48 hours; Frozen: 1 year

Testing Information

Performed

Testing performed once a day, 7 days a week. Specimen must be received in the Special Coagulation lab before 2:00 pm to be included in daily run.

Reported

HIT-AB RFLX: 1-2 days

SRA: 2-12 days, when reflexed

Method

Immunoassay, HemosIL HIT-Ab(PF4-H)

Referral Lab

ARUP 2005631 (SRA only)

Reference Values

Reference Values

Negative

CPT Codes

86022; if reflexed add 86022

Last Updated: Friday, January 8, 2021 02:03:03 AM


Client Services: 503-413-1234