The anti-PF4 (ie, heparin-induced platelet antibody) test is an immunologic, enzyme-linked immunosorbent assay (ELISA) that detects IgG antibodies against the platelet factor 4 (PF4)/heparin complex. The assay uses heparin bound to protamine sulfate, and PF4 is supplemented through a platelet lysate. The SRA test is a functional assay that ...

Dec 10, 2011 · Three types of assays are highly sensitive for the diagnosis of HIT: the washed platelet activation assays (SRA and HIPA), the IgG-specific PF4-dependent EIAs (EIA-IgG), and the polyspecific EIAs that detects anti-PF4/heparin antibodies of the 3 major immunoglobulin classes (EIA-IgG/A/M).

Heparin-induced thrombocytopenia (HIT) is a prothrombotic drug reaction caused by platelet-activating anti-platelet factor 4 (PF4)/heparin antibodies. Pathogenic HIT antibodies can be detected by the serotonin-release assay (SRA), a platelet activation test.

Diagnosis is made with a screening antiplatelet factor (PF4) immunoassay and the serotonin-release assay (SRA) as a confirmatory test. Anti-PF4 assays have high sensitivity (98%) but lower specificity (50%) and result in frequent false-positive tests.

Functional assays such as the 14 C serotonin–release assay (14 C-SRA) and heparin-induced platelet activation (HIPA) test are considered gold-standard tests for detecting pathological HIT antibodies.

Oct 14, 2022 · We describe a patient with a clinical course highly suspicious for HIT despite an initially weakly positive, then negative, PF4 antibody and repeatedly negative SRA. This should alert clinicians to the growing evidence of double-negative (PF4 …

Nov 15, 2022 · A new assay, the PF4-dependent P-selectin expression assay (PEA), has demonstrated comparable accuracy in HIT diagnosis employing a simpler laboratory technique. Herein, we report the real-world performance of a reference laboratory SRA and PEA and describe how incorporation of the PEA into the testing algorithm positively influenced the HIT ...

Heparin-induced thrombocytopenia (HIT), a prothrombotic drug reaction caused by platelet-activating anti-platelet factor 4 (PF4)/heparin antibodies, is commonly diagnosed with the platelet serotonin-release assay (SRA) or enzyme immunoassay (EIA).

Repeat PF4-H AB and SRA testing resulted positive. A positive SRA in the appropriate context is considered for the diagnosis of heparin-induced thrombocytopenia. This case report highlights that false-negative serological evaluation is possible early in the course of the disease.

The LabCorp Serotonin Release Assay (SRA) employs washed donor platelets and detects their activation by measuring the release of endogenous serotonin that is induced by addition of patient serum in the presence of heparin. Serotonin levels are measured by a highly sensitive liquid chromatography-tandem mass spectrometry method (LC/MS-MS).