Home Test Search Results Heparin Antibody (HIT) Screen – PF4 (reflex to confirmation)
Heparin Antibody (HIT) Screen – PF4 (reflex to confirmation)


Up to 5 percent of patients receiving heparin develop heparin-induced thrombocytopenia (HIT), a life-threatening complication that can occur following exposure to heparin, regardless of the dose, schedule, or route of administration. The mortality rate can be as high as 20 percent; with early diagnosis, mortality rates have been reported as low as 2 percent. Ruling out HIT quickly can achieve both significant cost savings and experience better patient outcomes. This is a highly sensitive screening test for clinical HIT, allowing rapid rule out with a negative result. Positive results should be confirmed with a functional assay to assess the ability of antibodies to activate platelets.

STAT: < 24 hours (7 days a week)


Draw Tube: Red Top

Sample Type: Serum


Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED Serum 1mL 0.5mL Room Temp.: 7 days
Refrigerated: 7 days
Frozen (-20C): 1 month
Frozen (-80C): 6 months
ALTERNATIVE Citrated Plasma 1mL - Frozen (-20C): 1 month
Frozen (-80C): 6 months
REJECTION CRITERIA Sample contamination; sample compromised

General Information

STAT TAT < 24 hours (7 days a week)
STAT TAT Performance > 90% of results released in 20 hours 7 days a week
ROUTINE TAT < 24 hours (M-F)
ALTERNATIVE NAMES PF4 antibody, platelet factor 4 antibody
DESCRIPTION Chromogenic ELISA for the qualitative determination of anti-platelet factor 4 (PF4)/heparin complex antibodies in human serum. Optical density (OD) values are reported for reference since OD correlates with the likelihood of HIT.
NORMAL RANGE Negative (OD < 0.400)

1. Linkins LA et al. Treatment and prevention of heparin-induced thrombocytopenia: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012; 141(2 Suppl):e495S-530S.
2. Multz AS et al. The Management of Suspected Heparin-Induced Thrombocytopenia in US Hospitals. Clin Appl Thromb Hemost. 2012; 20(1):68-72.
3. Warkentin TE et al. Laboratory testing for the antibodies that cause heparin-induced thrombocytopenia: how much class do we need? J Lab Clin Med. 200; 146(6):341-346.
4. Hess CN et al. Antithrombotic therapy in heparin-induced thrombocytopenia: guidelines translated for the clinician. J Thromb Thrombolysis. 2012; 34(4):552-561.
5. Cuker A et al. Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis. Blood. 2012; 120(20):4160-4167.

SAMPLE REPORT Upon request

Test Codes

CPT CODE 83520
LOINC CODE 73818-7