LOINCOrder

LOINC Code 55442-8: Antithrombin (PPP)

55442-8 is a LOINC code used to identify Antithrombin (PPP) 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 Antithrombin. 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 Antithrombin. 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: DEPRECATED
  • Order vs observation: Order

What it does not mean

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

Key facts

  • Deprecated Antithrombin in Platelet poor plasma
  • Antithrombin
  • Created ONLY for ORDERING in response to request from Canada Health Infoway- a national standardization effort. The dashes in this case mean that the ordering provider does not care what property or scale is used in the observation performed in response to this order. LOINC is still pondering details about how this kind of item should be represented. So the representation might change in the future, but the term will still have the same usage and meaning.
  • Anti thrombin; Antithrm; Antithrombin III; Antithrombn; AT; AT III; ATIII; Heparin cofactor I; Lab orders; LimitedUseLabOrders; Plas; Platelet poor plasma; Point in time; Random; Thrombin inhibitor I

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

Antithrombin (PPP)Deprecated Antithrombin in Platelet poor plasmaDeprecated AT III PPPAntithrombinLABORDERSAntithrombin, Blood-

Frequently asked questions

Code details

Code55442-8
SystemLOINC
Display nameAntithrombin (PPP)
DescriptionAntithrombin
Short nameDeprecated AT III PPP
ComponentAntithrombin
Property-
TimingPt
System (specimen)PPP
Scale-
ClassLABORDERS
StatusDEPRECATED
Order/ObservationOrder

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.27
Last changed2.66

Consumer names

Antithrombin, Blood

Part names

Antithrombin-PtPPPPoint in time (spot)Platelet poor 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.

LOINC Code 55442-8 | HealthAssure