LOINCActiveObservation

LOINC Code 9821-0: HIV 1 p24 Ag Ql (S)

9821-0 is a LOINC code used to identify HIV 1 p24 Ag Ql (S) 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 HIV 1 p24 Ag. It is commonly used with the system or sample type Ser.

Reviewed by HealthAssure Clinical TeamUpdated 25 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 HIV 1 p24 Ag. It is commonly used with the system or sample type Ser.

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: Observation

What it does not mean

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

Key facts

  • HIV 1 p24 Ag [Presence] in Serum
  • HIV 1 p24 Ag
  • AIDS; Antigen; Antigens; HIV type 1; HIV type I; HIV1; HIV1 p24; Human immunodeficiency virus; i; ID; Infectious Disease; InfectiousDisease; Microbiology; Ordinal; Point in time; PR; QL; Qual; Qualitative; Random; Screen; Serum; SR

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

HIV 1 p24 Ag Ql (S)HIV 1 p24 Ag [Presence] in SerumHIV1 p24 Ag Ser QlHIV 1 p24 AgMICROHIV 1 P24 antigen, BloodPrThr

Frequently asked questions

Code details

Code9821-0
SystemLOINC
Display nameHIV 1 p24 Ag Ql (S)
DescriptionHIV 1 p24 Ag
Short nameHIV1 p24 Ag Ser Ql
ComponentHIV 1 p24 Ag
PropertyPrThr
TimingPt
System (specimen)Ser
ScaleOrd
ClassMICRO
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0i
Last changed2.73

Consumer names

HIV 1 P24 antigen, Blood

Part names

HIV 1 p24 AgPrThrPtSerOrdPresence or ThresholdPoint in time (spot)Serum

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.

LOINC Code 9821-0 | HealthAssure