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LOINC Code 59231-1: Free PSA (CSF) [Mass/Vol]

59231-1 is a LOINC code used to identify Free PSA (CSF) [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 Prostate specific Ag.free. It is commonly used with the system or sample type CSF.

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 Prostate specific Ag.free. It is commonly used with the system or sample type CSF.

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

What it does not mean

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

Key facts

  • Prostate Specific Ag Free [Mass/volume] in Cerebral spinal fluid
  • Prostate specific Ag.free
  • Cerebral spinal fluid; Cerebrospinal Fl; Chemistry; fPSA; FR; Kallikrein 3; Level; Mass concentration; Non-protein bound; P-30 antigen; Point in time; PS; PSA; PSA Free; QNT; Quan; Quant; Quantitative; Random; Seminin; Spec; Spinal Fl; Spinal Fld; Spinal Flu; Spinal Fluid; Tumor marker

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

Free PSA (CSF) [Mass/Vol]Prostate Specific Ag Free [Mass/volume] in Cerebral spinal fluidPSA Free CSF-mCncProstate specific Ag.freeCHEMFree PSA, Spinal fluidMCnc

Frequently asked questions

Code details

Code59231-1
SystemLOINC
Display nameFree PSA (CSF) [Mass/Vol]
DescriptionProstate specific Ag.free
Short namePSA Free CSF-mCnc
ComponentProstate specific Ag.free
PropertyMCnc
TimingPt
System (specimen)CSF
ScaleQn
ClassCHEM
Example unitsug/L
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.32
Last changed2.70

Consumer names

Free PSA, Spinal fluid

Part names

Prostate specific Ag.freeMCncPtCSFQnProstate Specific Ag FreeMass ConcentrationPoint in time (spot)Cerebral spinal fluid

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 59231-1 | HealthAssure