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Order Code HITIG Heparin-PF4 IgG Antibody, Serum

Useful For

Detection of IgG antibodies directed against heparin/platelet factor 4 complexes that are implicated in the pathogenesis of immune-mediated type II heparin-induced thrombocytopenia, spontaneous heparin platelet-factor 4 IgG antibody, and thrombocytopenia and thrombosis occurring after SARS-CoV2 adenovirus vector vaccine

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

Heparin-PF4 IgG Ab (HIT), S

Specimen Type

Serum Red


Specimen Required


Patient Preparation:

Fasting: 8 hours, preferred but not required

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.

Specimen Stability Information: Frozen (preferred) 2 years/Refrigerate 7 days


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Frozen (preferred)
  Refrigerated  7 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject

Reference Values

HIT ELISA:

<0.400

 

HIT Interpretation:

Negative

Method Description

Enzyme-linked immunosorbent assay (ELISA) testing is performed on the Janus G3 integrated liquid handling system and BioTek plate reader using the Immucor GTI Diagnostics, Inc PF4 IgG assay test kit. Patient serum is incubated in microwells precoated with an antigen complex of platelet factor 4 (PF4) and polyanionic heparinoid substitute (polyvinyl sulfonate; PVS). If antibodies to this complex are present in the patient serum, they will bind to the PF4:PVS antigen complex; all other antibodies are washed away. An anti-IgG reagent (conjugate) is added to the wells, incubated, and washed to remove any unbound conjugate. P-Nitrophenylphosphate is added and incubated; color is generated when bound conjugate cleaves a chromogenic phosphate substrate. The reaction is stopped, and the absorbance measured using a spectrophotometer at 405 nm.

 

Addition of excess heparin (100 U/mL) to patient serum prior to testing inhibits the reaction between heparin-dependent antibodies and the PF4:PVS complex and decreases absorbance (reactivity). This procedure is used to confirm a positive screening result is caused by heparin-dependent antibodies. Results are calculated as the percent heparin inhibition of the reactivity of the antibody.(Collins JL, Aster RH, Moghaddam M, et al. Diagnostic testing for heparin-induced thrombocytopenia [HIT]: An enhanced platelet factor 4 complex enzyme linked immunosorbent assay [PF4 ELISA]. Blood. 1997 [Suppl 1] 90:461a; package insert: PF4 IgG assay. Immucor GTI Diagnostics, Inc; Rev D, 05/2015)

Day(s) Performed

Monday through Sunday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

86022