Test Catalog

Test ID: HITIG    
Heparin-PF4 IgG Antibody (HIT), Serum

Method Description Describes how the test is performed and provides a method-specific reference

The human platelet factor 4 (H/PF4) IgG antibody immunoassay is an enzyme-linked immunosorbent assays (ELISA) using microwells precoated with an antigen complex of PF4 and polyanionic heparinoid substitute (polyvinyl sulfonate; PVS). Testing is performed on the Biomek FXP liquid handling system using the Immucor GTI Diagnostics, Inc. PF4 IgG assay test kit. Patient serum is incubated in the wells, and binding of antibodies to this complex is detected by binding of a second phosphatase-conjugated antihuman IgG antibody. Color is generated when this bound conjugate cleaves a chromogenic phosphate substrate, and is quantitated by light absorption 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 produces a negative result. This procedure is used to confirm that 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. Waukesha, WI, Rev D 5/2015)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.

Monday through Sunday, Varies

Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.

1 day

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Clinic Laboratories until the release of the test result

3 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location Indicates the location of the laboratory that performs the test