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LOINC Code 55894-0: Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase (Placenta) [Catalytic ratio]

55894-0 is a LOINC code used to identify Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase (Placenta) [Catalytic 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 Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase. It is commonly used with the system or sample type Placenta.

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 Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase. It is commonly used with the system or sample type Placenta.

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

  • Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase [Enzymatic activity ratio] in Placenta
  • Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase
  • Adenine transaminase; APRT; B4 Hemosan; Catalytic Concentration Ratio; Catalytic Ratio; CCrto; Chemistry; Enzymatic activity ratio; HGPRT; HPRT; hypoxanthine-guanine phosphoribosyltransferase; Leuco-4; Placent; Placental; Point in time; QNT; Quan; Quant; Quantitative; Random; Vit B4; Vitamin B4

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

Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase (Placenta) [Catalytic ratio]Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase [Enzymatic activity ratio] in PlacentaHPRT/APRT Placenta-cRtoHypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferaseCHEMHypoxanthine phosphoribosyltransferase/Adenine Phosphoribosyltransferase, PlacentaCRto

Frequently asked questions

Code details

Code55894-0
SystemLOINC
Display nameHypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase (Placenta) [Catalytic ratio]
DescriptionHypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase
Short nameHPRT/APRT Placenta-cRto
ComponentHypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferase
PropertyCRto
TimingPt
System (specimen)Placenta
ScaleQn
ClassCHEM
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.29
Last changed2.63

Consumer names

Hypoxanthine phosphoribosyltransferase/Adenine Phosphoribosyltransferase, Placenta

Part names

Hypoxanthine phosphoribosyltransferase/Adenine phosphoribosyltransferaseCRtoPtPlacentaQnCatalytic RatioPoint in time (spot)

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.