Heparin Antibody (HIT) Screen – PF4 (reflex to confirmation)

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Justification

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)

ELISA

Draw Tube: Red Top

Sample Type: Serum

Draw Kits Available

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
SPECIAL INSTRUCTIONS	-

General Information

METHODOLOGY	ELISA
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.
LIMITATIONS	-
NORMAL RANGE	Negative (OD < 0.400)
ASSOCIATED TESTING	-
REFERENCES	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
NEW YORK STATE APPROVED	Yes

Test Codes

ORDER CODE	P3060
CPT CODE	83520
LOINC CODE	73818-7