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 17651-1: S. pneumoniae IgG spec 2 IA Qn (S)

Name: LOINC Code 17651-1: S. pneumoniae IgG spec 2 IA Qn (S)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T11:17:26.982Z

17651-1 is a LOINC code used to identify S. pneumoniae IgG spec 2 IA Qn (S) 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 Streptococcus pneumoniae Ab.IgG^2nd specimen. It is commonly used with the system or sample type Ser.

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 Streptococcus pneumoniae Ab.IgG^2nd specimen. It is commonly used with the system or sample type Ser.

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

Streptococcus pneumoniae IgG Ab [Units/volume] in Serum by Immunoassay --2nd specimen
Streptococcus pneumoniae Ab.IgG^2nd specimen
ABS; Aby; Antby; Anti; Antibodies; Antibody; Arbitrary concentration; Autoantibodies; Autoantibody; Convalescent; EIA; ELFA; ELISA; Enzyme immunoassay; IAA; ID; Immune globulin G; Immunoglobulin G; Infectious Disease; InfectiousDisease; MEIA; Microbiology; Pneu; pneum; Pneumo; Pneumococ; Pneumococcal; Pneumococcal pneumonia; Pneumococcus; Pneumon; Pneumonia; Point in time; Post immunization; QNT; Quan; Quant; Quantitative; Random; S pneumo; S pneumoniae; Second; Serum; sp2; Spec; Spn; SR; Strep; Strept; 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

S. pneumoniae IgG spec 2 IA Qn (S)Streptococcus pneumoniae IgG Ab [Units/volume] in Serum by Immunoassay --2nd specimenS pneum IgG sp2 Ser IA-aCncStreptococcus pneumoniae Ab.IgG^2nd specimenMICROStreptococcus pneumoniae IgG antibody specimen 2, BloodACnc

Frequently asked questions

Code details

Code17651-1

SystemLOINC

Display nameS. pneumoniae IgG spec 2 IA Qn (S)

DescriptionStreptococcus pneumoniae Ab.IgG^2nd specimen

Short nameS pneum IgG sp2 Ser IA-aCnc

ComponentStreptococcus pneumoniae Ab.IgG^2nd specimen

PropertyACnc

TimingPt

System (specimen)Ser

ScaleQn

MethodIA

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0l

Last changed2.69

Consumer names

Streptococcus pneumoniae IgG antibody specimen 2, Blood

Part names

Streptococcus pneumoniae Ab.IgG^2nd specimenACncPtSerQnIAArbitrary ConcentrationPoint in time (spot)SerumImmunoassay

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.