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LOINC Code 41027-4: Tau protein/Amyloid beta 42 peptide (CSF) [Ratio]

41027-4 is a LOINC code used to identify Tau protein/Amyloid beta 42 peptide (CSF) [Ratio] 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 Tau protein/Amyloid beta 42 peptide. 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 Tau protein/Amyloid beta 42 peptide. 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

  • Tau protein/Amyloid beta 42 peptide [Ratio] in Cerebral spinal fluid
  • Tau protein/Amyloid beta 42 peptide
  • Ab42 peptide; Abeta; Abeta 42; AL beta42; Alzheimer disease; Alzheimer's disease; B; Beta-amyloid; Cerebral spinal fluid; Cerebrospinal Fl; Chemistry; Neuro; Neurology; Pept; Point in time; PR; Prot; QNT; Quan; Quant; Quantitative; Random; Ratios; Rto; Spinal Fl; Spinal Fld; Spinal Flu; Spinal Fluid

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

Tau protein/Amyloid beta 42 peptide (CSF) [Ratio]Tau protein/Amyloid beta 42 peptide [Ratio] in Cerebral spinal fluidTau Prot/AL beta42 CSF-RtoTau protein/Amyloid beta 42 peptideCHEMTau protein/Amyloid Beta 42 Peptide, Spinal fluidRatio

Frequently asked questions

Code details

Code41027-4
SystemLOINC
Display nameTau protein/Amyloid beta 42 peptide (CSF) [Ratio]
DescriptionTau protein/Amyloid beta 42 peptide
Short nameTau Prot/AL beta42 CSF-Rto
ComponentTau protein/Amyloid beta 42 peptide
PropertyRatio
TimingPt
System (specimen)CSF
ScaleQn
ClassCHEM
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.15
Last changed2.73

Consumer names

Tau protein/Amyloid Beta 42 Peptide, Spinal fluid

Part names

Tau protein/Amyloid beta 42 peptideRatioPtCSFQnPoint 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.