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.

LOINCActiveBoth

LOINC Code 40457-4: Prothrombin Ab Qn

Name: LOINC Code 40457-4: Prothrombin Ab Qn
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

40457-4 is a LOINC code used to identify Prothrombin Ab Qn 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 Prothrombin Ab. It is commonly used with the system or sample type Ser/Plas.

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 Prothrombin Ab. It is commonly used with the system or sample type Ser/Plas.

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

What it does not mean

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

Key facts

Prothrombin Ab [Units/volume] in Serum or Plasma
Prothrombin Ab
ABS; Aby; Antby; Anti; Antibodies; Antibody; Arbitrary concentration; Autoantibodies; Autoantibody; COAGULATION; Coagulation factor II; Factor 2; Factor II; Hematology; Heme; Pl; Plasma; Plsm; Point in time; Prothombin; Prothrm; Prothromb; QNT; Quan; Quant; Quantitative; Random; SerP; SerPl; SerPlas; Serum; Serum or plasma; 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.

Related SNOMED CT concepts

705114005SNOMED CT mapping for Prothrombin Ab Qn (40457-4)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

Prothrombin Ab QnProthrombin Ab [Units/volume] in Serum or PlasmaProthrom Ab SerPl-aCncProthrombin AbCOAGProthrombin antibody, BloodACnc

Frequently asked questions

Code details

Code40457-4

SystemLOINC

Display nameProthrombin Ab Qn

DescriptionProthrombin Ab

Short nameProthrom Ab SerPl-aCnc

ComponentProthrombin Ab

PropertyACnc

TimingPt

System (specimen)Ser/Plas

ScaleQn

ClassCOAG

Example unitsarb U/mL

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.15

Last changed2.73

Consumer names

Prothrombin antibody, Blood

Part names

Prothrombin AbACncPtSer/PlasQnArbitrary ConcentrationPoint in time (spot)Serum or Plasma

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.