What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveBoth

LOINC Code 90821-0: Contactin-associated protein 2 Ab Cell binding immunofluorescent assay (CSF) [Titer]

Name: LOINC Code 90821-0: Contactin-associated protein 2 Ab Cell binding immunofluorescent assay (CSF) [Titer]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T09:00:20.875Z

90821-0 is a LOINC code used to identify Contactin-associated protein 2 Ab Cell binding immunofluorescent assay (CSF) [Titer] 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 Contactin-associated protein 2 Ab. 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 Contactin-associated protein 2 Ab. 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: CBA IFA

What it does not mean

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

Key facts

Contactin-associated protein 2 Ab [Titer] in Cerebral spinal fluid by Cell binding immunofluorescent assay
Contactin-associated protein 2 Ab
ABS; Aby; Antby; Anti; Antibodies; Antibody; Assoc; Autoantibodies; Autoantibody; CASPR2; CASPR2 Ab; Cerebral spinal fluid; Cerebrospinal Fl; Dilution factor; Dilution Factor (Titer); II; Indirect Fluorescence Antibody; Point in time; PR; Prot; Random; Serology; SmQn; Spinal Fl; Spinal Fld; Spinal Flu; Spinal Fluid; Titer; Titered; Titre; Ttr

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

Contactin-associated protein 2 Ab Cell binding immunofluorescent assay (CSF) [Titer]Contactin-associated protein 2 Ab [Titer] in Cerebral spinal fluid by Cell binding immunofluorescent assayCASPR2 Ab Titr CSF CBA IFAContactin-associated protein 2 AbSEROContactin-associated protein 2 antibody, Spinal fluidTitr

Frequently asked questions

Code details

Code90821-0

SystemLOINC

Display nameContactin-associated protein 2 Ab Cell binding immunofluorescent assay (CSF) [Titer]

DescriptionContactin-associated protein 2 Ab

Short nameCASPR2 Ab Titr CSF CBA IFA

ComponentContactin-associated protein 2 Ab

PropertyTitr

TimingPt

System (specimen)CSF

ScaleSemiQn

MethodCBA IFA

ClassSERO

Example unitstiter

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.65

Last changed2.75

Consumer names

Contactin-associated protein 2 antibody, Spinal fluid

Part names

Contactin-associated protein 2 AbTitrPtCSFSemiQnCBA IFATiterPoint in time (spot)Cerebral spinal fluidCell binding immunofluorescent assay

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.