LOINCActiveBoth

LOINC Code 27821-8: Protein S Free Ag actual/normal IA (PPP) [Relative mass conc]

27821-8 is a LOINC code used to identify Protein S Free Ag actual/normal IA (PPP) [Relative mass conc] 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 Protein S.free Ag actual/Normal. It is commonly used with the system or sample type PPP.

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 Protein S.free Ag actual/Normal. It is commonly used with the system or sample type PPP.

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: IA

What it does not mean

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

Key facts

  • Protein S Free Ag actual/normal in Platelet poor plasma by Immunoassay
  • Protein S.free Ag actual/Normal
  • Act/Nor; Ag Act/Nor; Antigen; Antigens; COAGULATION; Control; EIA; ELFA; ELISA; Enzyme immunoassay; FR; Hematology; Heme; IAA; MEIA; Non-protein bound; Plas; Platelet poor plasma; Point in time; PR; Prot; Prot S; Prot S Free; PS; QNT; Quan; Quant; Quantitative; Random; Relative mass concentration; RLMCNC; S prime; SUDS; UniversalLabOrders

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

Protein S Free Ag actual/normal IA (PPP) [Relative mass conc]Protein S Free Ag actual/normal in Platelet poor plasma by ImmunoassayProt S Free Ag Act/Nor PPP IAProtein S.free Ag actual/NormalCOAGFree Protein S antigen activity, BloodRelMCnc

Frequently asked questions

Code details

Code27821-8
SystemLOINC
Display nameProtein S Free Ag actual/normal IA (PPP) [Relative mass conc]
DescriptionProtein S.free Ag actual/Normal
Short nameProt S Free Ag Act/Nor PPP IA
ComponentProtein S.free Ag actual/Normal
PropertyRelMCnc
TimingPt
System (specimen)PPP
ScaleQn
MethodIA
ClassCOAG
Example units%
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.00
Last changed2.73

Consumer names

Free Protein S antigen activity, Blood

Part names

Protein S.free Ag actual/NormalRelMCncPtPPPQnIARelative Mass ConcentrationPoint in time (spot)Platelet poor plasmaImmunoassay

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 27821-8 | HealthAssure