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LOINC Code 33877-2: Tetrahydrobiopterin/Biopterin (U) [Molar fraction]

33877-2 is a LOINC code used to identify Tetrahydrobiopterin/Biopterin (U) [Molar fraction] 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 Tetrahydrobiopterin/Biopterin. It is commonly used with the system or sample type Urine.

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 Tetrahydrobiopterin/Biopterin. It is commonly used with the system or sample type Urine.

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

  • Tetrahydrobiopterin/Biopterin in Urine
  • Tetrahydrobiopterin/Biopterin
  • A low %BH4 is characteristic of dihydropteridine reductase deficiency, which leads to phenylalanine hydroxylase deficiency, which lesds to phenylketonuria
  • BH4; BH4 deficiency; BIOPT; Biopterin deficiency; Biopterin H4; Chemistry; Hyperphenylalaninaemia; Percent; Point in time; QNT; Quan; Quant; Quantitative; Random; Substance fraction; UA; UR; Urn

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

Tetrahydrobiopterin/Biopterin (U) [Molar fraction]Tetrahydrobiopterin/Biopterin in UrineBiopterin H4/Biopterin SFr UrTetrahydrobiopterin/BiopterinCHEMTetrahydrobiopterin/Biopterin, UrineSFr

Frequently asked questions

Code details

Code33877-2
SystemLOINC
Display nameTetrahydrobiopterin/Biopterin (U) [Molar fraction]
DescriptionTetrahydrobiopterin/Biopterin
Short nameBiopterin H4/Biopterin SFr Ur
ComponentTetrahydrobiopterin/Biopterin
PropertySFr
TimingPt
System (specimen)Urine
ScaleQn
ClassCHEM
Example unitsumol/umol
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.09
Last changed2.70

Consumer names

Tetrahydrobiopterin/Biopterin, Urine

Part names

Tetrahydrobiopterin/BiopterinSFrPtUrineQnSubstance FractionPoint 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.