What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveObservation

LOINC Code 58481-3: Protein C Ag/Coagulation factor IX Ag IA (PPP) [Mass ratio]

Name: LOINC Code 58481-3: Protein C Ag/Coagulation factor IX Ag IA (PPP) [Mass ratio]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:39.275Z

58481-3 is a LOINC code used to identify Protein C Ag/Coagulation factor IX Ag IA (PPP) [Mass ratio] 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 C Ag/Coagulation factor IX Ag. 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 C Ag/Coagulation factor IX Ag. 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: Observation
Method: IA

What it does not mean

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

Key facts

Protein C Ag/Coagulation factor IX Ag [Mass Ratio] in Platelet poor plasma by Immunoassay
Protein C Ag/Coagulation factor IX Ag
Antigen; Antigens; Antihemophilic factor B; Autoprothrombin II-a; Christmas factor; Coag; EIA; ELFA; ELISA; Enzyme immunoassay; Fac; Fact; Fact IX; Factor 9; FIX; Hematology; Heme; IAA; Mass concentration ratio; Mass ratio; MCRto; MEIA; PC; Plas; Plasma thromboplastin component; Platelet poor plasma; Point in time; PR; Prot; Prot C; PTC; QNT; Quan; Quant; Quantitative; Random; Rh; Rh Blood Group System; SUDS; Thrombocyte cofactor II

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 C Ag/Coagulation factor IX Ag IA (PPP) [Mass ratio]Protein C Ag/Coagulation factor IX Ag [Mass Ratio] in Platelet poor plasma by ImmunoassayProt C Ag/Fact IX Ag PPP IAProtein C Ag/Coagulation factor IX AgCOAGProtein C Antigen/Coagulation Factor IX Antigen, BloodMRto

Frequently asked questions

Code details

Code58481-3

SystemLOINC

Display nameProtein C Ag/Coagulation factor IX Ag IA (PPP) [Mass ratio]

DescriptionProtein C Ag/Coagulation factor IX Ag

Short nameProt C Ag/Fact IX Ag PPP IA

ComponentProtein C Ag/Coagulation factor IX Ag

PropertyMRto

TimingPt

System (specimen)PPP

ScaleQn

MethodIA

ClassCOAG

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.32

Last changed2.73

Consumer names

Protein C Antigen/Coagulation Factor IX Antigen, Blood

Part names

Protein C Ag/Coagulation factor IX AgMRtoPtPPPQnIAMass RatioPoint 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.