91120-6

LOINC code 91120-6 identifies "Antithrombin in Platelet poor plasma by Chromo.no addition of heparin". This term represents an antithrombin (AT) assay which, in contrast to typical AT assays, is performed in the ABSENCE of heparin. This assay is also known as "Progressive antithrombin assay." It is used to identify type IIb AT deficiency, which is caused by a mutation in the AT heparin binding site (HBS). In type IIb AT deficiency, AT activity is reduced in the presence of heparin but is normal in the absence of heparin.[PMID: 19141163] This term was created for, but is not limited in use to, the Biophen Antithrombin 5 assay's VARIANT Method, which is performed without heparin. In patients with type IIb AT deficiency, AT activity is expected to be normal in patients with an HBS mutation.

This code measures Antithrombin in PPP. It belongs to the COAG class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.