LOINCActiveBoth

LOINC Code 101649-2: Tau protein IA (CSF) [Mass/Vol]

101649-2 is a LOINC code used to identify Tau protein IA (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 Tau protein. It is commonly used with the system or sample type CSF.

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 Tau protein. 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
  • Method: IA

What it does not mean

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

Key facts

  • Tau protein [Mass/volume] in Cerebral spinal fluid by Immunoassay
  • Tau protein
  • Alzheimer disease; Alzheimer's disease; Cerebral spinal fluid; Cerebrospinal Fl; Chemistry; EIA; ELFA; ELISA; Enzyme immunoassay; IAA; Level; Mass concentration; MEIA; Point in time; PR; Prot; QNT; Quan; Quant; Quantitative; Random; Spinal Fl; Spinal Fld; Spinal Flu; Spinal Fluid; SUDS

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 IA (CSF) [Mass/Vol]Tau protein [Mass/volume] in Cerebral spinal fluid by ImmunoassayTau Prot CSF IA-mCncTau proteinCHEMTau protein, Spinal fluidMCnc

Frequently asked questions

Code details

Code101649-2
SystemLOINC
Display nameTau protein IA (CSF) [Mass/Vol]
DescriptionTau protein
Short nameTau Prot CSF IA-mCnc
ComponentTau protein
PropertyMCnc
TimingPt
System (specimen)CSF
ScaleQn
MethodIA
ClassCHEM
Example unitsmg/dL
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.75
Last changed2.75

Consumer names

Tau protein, Spinal fluid

Part names

Tau proteinMCncPtCSFQnIAMass ConcentrationPoint in time (spot)Cerebral spinal fluidImmunoassay

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 101649-2 | HealthAssure