Heparin-Induced Thrombocytopenia Panel

Test Code

14874

CPT Codes
86022 (x2)

Includes

Serotonin Release Assay (SRA), Unfractionated Heparin
Heparin-Induced Platelet Antibody

Preferred Specimen

1 mL serum collected in each of two separate red-top tubes (no gel)

Minimum Volume

0.9 mL (x2)

Instructions

Centrifuge red top tube 15 minutes at approximately 1500g as soon as possible after clotting

Transport Container

Transport tube (x2)

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 6 months

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Gross hemolysis • Lipemia • Icteric • Serum separator tube (SST)

Methodology
Enzyme Immunoassay (EIA) • Radiobinding Assay (RBA)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Mon-Fri; Report available: 3-4 days

Limitations

When heparin is stopped, antibody that may have been present disappears within weeks to months.

Reference Range

See individual tests

Clinical Significance

This panel helps diagnose heparin-induced thrombocytopenia (HIT) in individuals exposed to unfractionated heparin (UFH). The diagnosis of HIT is based on clinical criteria, but serological confirmation is often necessary [1].

HIT is a severe immune reaction to heparin therapy and is associated with high risk of venous and arterial thrombosis, making diagnosis and management critical for patient care. HIT is suspected when platelet counts decrease within 1 to 10 days after initiation of the treatment. Certain patient populations are known to have high risk of developing HIT from heparin-based therapy, such as those receiving UFH therapy after surgery (1%-5% incidence of HIT) [2,3].

The American Society of Hematology (ASH) suggests screening for HIT by monitoring platelet counts in patients undergoing heparin therapy for whom risk of HIT is considered intermediate or high [2]. Patients with decreased platelet count have increased probability of HIT, in which case further assessment is recommended to obtain a 4Ts clinical prediction score [2].

For patients with an intermediate or high 4Ts score, ASH recommends an immunoassay to detect the presence of HIT antibodies [2]. If the immunoassay results are positive, ASH suggests a functional assay, such as a serotonin release assay, to assess heparin-induced platelet activation and further confirm a HIT diagnosis [3].

Quest Diagnostics offers an immunoassay to detect heparin-induced platelet antibodies (Heparin-Induced Platelet Antibody) and a serotonin release assay (Serotonin Release Assay [SRA], Unfractionated Heparin) to confirm a HIT diagnosis in patients exposed to UFH. These 2 tests may be ordered individually, together as this panel, or as a reflex test (Heparin-Induced Platelet Antibody with Reflex to SRA, Unfractionated Heparin). Test selection is based on the healthcare provider's needs and institutional capabilities.

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. Higgins RA, et al. Platelets and van Willebrand factor. In: Rifai R, et al, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier Inc; 2022.
2. Cuker A, et al. Blood Adv. 2018;2(22):3360-3392.
3. Guyatt GH, et al. Chest. 2012;141(2 Suppl):53S-70S.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.