LOINCActiveObservation

LOINC Code 12964-3: Urea nitrogen baseline (Bld) [Mass/Vol]

12964-3 is a LOINC code used to identify Urea nitrogen baseline (Bld) [Mass/Vol] 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 Urea nitrogen^baseline. It is commonly used with the system or sample type Bld.

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 Urea nitrogen^baseline. It is commonly used with the system or sample type Bld.

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

  • Urea nitrogen [Mass/volume] in Blood --baseline
  • Urea nitrogen^baseline
  • Blood; Blood urea nitrogen; BS; BUN; Chemistry; Kidney; Level; Mass concentration; N; N2; Nephrology; Nit; Point in time; QNT; Quan; Quant; Quantitative; Random; Renal; UN; WB; Whole blood

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

Urea nitrogen baseline (Bld) [Mass/Vol]Urea nitrogen [Mass/volume] in Blood --baselineBUN BS Bld-mCncUrea nitrogen^baselineCHEMUrea Nitrogen (BUN) baseline, BloodMCnc

Frequently asked questions

Code details

Code12964-3
SystemLOINC
Display nameUrea nitrogen baseline (Bld) [Mass/Vol]
DescriptionUrea nitrogen^baseline
Short nameBUN BS Bld-mCnc
ComponentUrea nitrogen^baseline
PropertyMCnc
TimingPt
System (specimen)Bld
ScaleQn
ClassCHEM
Example unitsmg/dL
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0j-a
Last changed2.40

Consumer names

Urea Nitrogen (BUN) baseline, Blood

Part names

Urea nitrogen^baselineMCncPtBldQnMass ConcentrationPoint in time (spot)Blood

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 12964-3 | HealthAssure