LOINCActiveObservation

LOINC Code 29638-4: Specimen weight (Tiss)

29638-4 is a LOINC code used to identify Specimen weight (Tiss) 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 Specimen weight. It is commonly used with the system or sample type Tiss.

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 Specimen weight. It is commonly used with the system or sample type Tiss.

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

  • Weight of Tissue
  • Specimen weight
  • Point in time; QNT; Quan; Quant; Quantitative; Random; Spec; Specimen wt; Tissue; Tissue, unspecified; Wt

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

Specimen weight (Tiss)Weight of TissueSpecimen wt Tiss QnSpecimen weightSPECSpecimen weight, TissueMass

Frequently asked questions

Code details

Code29638-4
SystemLOINC
Display nameSpecimen weight (Tiss)
DescriptionSpecimen weight
Short nameSpecimen wt Tiss Qn
ComponentSpecimen weight
PropertyMass
TimingPt
System (specimen)Tiss
ScaleQn
ClassSPEC
Example unitsmg
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.03
Last changed2.73

Consumer names

Specimen weight, Tissue

Part names

Specimen weightMassPtTissQnPoint in time (spot)Tissue and Smears

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 29638-4 | HealthAssure