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LOINC Code 81321-2: FLUAV H5 Asian RNA NAA+probe primer-probe set H5b (Respiratory system specimen) [ThreshNum]

81321-2 is a LOINC code used to identify FLUAV H5 Asian RNA NAA+probe primer-probe set H5b (Respiratory system specimen) [ThreshNum] in laboratory and clinical observation data. You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges. LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Influenza virus A H5 Asian RNA. It is commonly used with the system or sample type Respiratory System Specimen.

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Influenza virus A H5 Asian RNA. It is commonly used with the system or sample type Respiratory System Specimen.

When is it used?

  • Used in lab systems, EHRs, and clinical data exchange.
  • May identify a test, observation, survey item, or clinical document request rather than a diagnosis.
  • Status: ACTIVE
  • Order vs observation: Both
  • Method: Probe.amp.tar.primer-probe set H5b

What it does not mean

  • The code identifies the observation or test, not the actual result.

Key facts

Influenza virus A H5 Asian RNA [Cycle Threshold #] in Respiratory system specimen by Nucleic acid amplification using primer-probe set H5b
Influenza virus A H5 Asian RNA
This term represents the identification of the Influenza A H5 subtype based on the H5b probe and primer set provided by the Centers for Disease Control and Prevention. "H5b" does not refer to a more specific type of the H5 virus, rather it is the name of one of the two primer and probe sets (the other is H5a) that are used to detect the Influenza A H5 subtype. For presumptive positive identification of the H5 subtype, results for both the H5a and H5b assays should be positive. If one is positive and one is negative, the result is inconclusive for the H5 subtype. Possible specimens includeupper respiratory tract clinical specimens (including nasopharyngeal swabs, nasal swabs, throat swabs, nasal aspirates, nasal washes, and dual nasopharyngeal/throat swabs), and lower respiratory tract specimens (including bronchoalveolar lavage, bronchial wash, tracheal aspirate, sputum, and lung tissue.
3 Self-Sustaining Sequence Replication; 3SR SR; Amplif; Amplification; Amplified; Avian influenza; Bird flu; Breathing; DNA NUCLEIC ACID PROBE; DNA probe; FLUA; FLUAV; FLUAV H5; FLUAV H5 Asian; FLUV; Fowl plague; ID; Infectious Disease; InfectiousDisease; Influ; Influenza A; Influenza A virus; LAT; LCR; Ligase chain reaction; Ligation-activated transcription; Lung; Lungs; Microbiology; NAA H5b; NAA+probe; NAAT; NASBA; Nucleic acid sequence based analysis; PCR; PH; Point in time; Polymerase chain reaction; Probe amp; Probe with ampification; Probe with target amplification; Public Health; PublicHealth; Pulmonary; Pulmonology; QBR; QNT; Quan; Quant; Quantitative; Random; Respiratory; Ribonucleic acid; RS; SDA; Spec; Strand Displacement Amplification; TMA; Transcription mediated amplification

Where you may see this code

You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges.

Common synonyms

FLUAV H5 Asian RNA NAA+probe primer-probe set H5b (Respiratory system specimen) [ThreshNum]Influenza virus A H5 Asian RNA [Cycle Threshold #] in Respiratory system specimen by Nucleic acid amplification using primer-probe set H5bFLUAV H5 Asian RNA Ct Resp Qn NAA H5bInfluenza virus A H5 Asian RNAMICROInfluenza A H5 Asian, Respiratory system specimenThreshNum

Frequently asked questions

Code details

Code81321-2
SystemLOINC
Display nameFLUAV H5 Asian RNA NAA+probe primer-probe set H5b (Respiratory system specimen) [ThreshNum]
DescriptionInfluenza virus A H5 Asian RNA
Short nameFLUAV H5 Asian RNA Ct Resp Qn NAA H5b
ComponentInfluenza virus A H5 Asian RNA
PropertyThreshNum
TimingPt
System (specimen)Respiratory System Specimen
ScaleQn
MethodProbe.amp.tar.primer-probe set H5b
ClassMICRO
Example unitsCt
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.56
Last changed2.75

Consumer names

Influenza A H5 Asian, Respiratory system specimen

Part names

Influenza virus A H5 asian RNAThreshNumPtRespiratory System SpecimenQnProbe.amp.tar.primer-probe set H5bPoint in time (spot)Nucleic acid amplification using primer-probe set H5b

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from LOINC. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.