77605-4

LOINC code 77605-4 identifies "Influenza virus A H5 RNA [Cycle Threshold #] in Specimen by NAA with probe detection". The goose/Guangdong lineage H5 viruses emerged in the late 90s in Asia and subsequently became the only lineage of viruses known to be highly pathogenic to poultry and sustained in wild birds. The World Health Organization recognizes these viruses under a unified H5 clade nomenclature. Viruses from this lineage, specifically clade 2.3.4.4, were introduced into North American flyways in late 2014 via the Bering Strait into the Pacific flyway and again in late 2021 into the Atlantic flyway. [PMID:25855748] The NALHN influenza A molecular assay (matrix 2009) works well for the detection of this viral clade and is the primary surveillance tool. As a screening tool, the NAHLN H5 assay does not distinguish geographic lineage nor pathotype (LPAI vs HPAI). This clade specific assay uses real-time reverse transcriptase PCR targeted to clade H5 2.3.4.4.

This code measures Influenza virus A H5 RNA in XXX. It belongs to the MICRO 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.