LOINCActiveBoth

LOINC Code 21391-8: Microscopic observation Acid phosphatase stain Nom (Bone)

21391-8 is a LOINC code used to identify Microscopic observation Acid phosphatase stain Nom (Bone) 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 Observation. It is commonly used with the system or sample type Bone.

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 Observation. It is commonly used with the system or sample type Bone.

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: Both
  • Method: Acid phosphatase stain

What it does not mean

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

Key facts

  • Microscopic observation [Identifier] in Bone by Acid phosphatase stain
  • Observation
  • Acd; Acids; ACP Stn; BON; Identity or presence; Nominal; Pathology; Phos; Phosphtase; Point in time; Random; St; Stains; Stn

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

Microscopic observation Acid phosphatase stain Nom (Bone)Microscopic observation [Identifier] in Bone by Acid phosphatase stainACP Stn BoneObservationPATHMicroscopic observation, BonePrid

Frequently asked questions

Code details

Code21391-8
SystemLOINC
Display nameMicroscopic observation Acid phosphatase stain Nom (Bone)
DescriptionObservation
Short nameACP Stn Bone
ComponentObservation
PropertyPrid
TimingPt
System (specimen)Bone
ScaleNom
MethodAcid phosphatase stain
ClassPATH
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0m
Last changed2.78

Consumer names

Microscopic observation, Bone

Part names

ObservationPridPtBoneNomAcid phosphatase stainPresence or IdentityPoint 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.

LOINC Code 21391-8 | HealthAssure