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.

LOINC

LOINC Code 63909-6: Year of diagnosis of clinician-diagnosed illness [PhenX]

Name: LOINC Code 63909-6: Year of diagnosis of clinician-diagnosed illness [PhenX]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:43.947Z

63909-6 is a LOINC code used to identify Year of diagnosis of clinician-diagnosed illness [PhenX] 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 Y of diagnosis of clinician-diagnosed illness. It is commonly used with the system or sample type ^Patient.

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 Y of diagnosis of clinician-diagnosed illness. It is commonly used with the system or sample type ^Patient.

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: TRIAL
Method: PhenX

What it does not mean

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

Key facts

Year of diagnosis of clinician-diagnosed illness [PhenX]
Y of diagnosis of clinician-diagnosed illness
Dx; Point in time; Pre-existing condition Y; QNT; Quan; Quant; Quantitative; Random

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

Year of diagnosis of clinician-diagnosed illness [PhenX]Pre-existing condition Y PhenXY of diagnosis of clinician-diagnosed illnessPHENXDatePt^Patient

Frequently asked questions

Code details

Code63909-6

SystemLOINC

Display nameYear of diagnosis of clinician-diagnosed illness [PhenX]

DescriptionY of diagnosis of clinician-diagnosed illness

Short namePre-existing condition Y PhenX

ComponentY of diagnosis of clinician-diagnosed illness

PropertyDate

TimingPt

System (specimen)^Patient

ScaleQn

MethodPhenX

ClassPHENX

Example unitsYYYY

StatusTRIAL

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.36

Last changed2.65

Part names

Y of diagnosis of clinician-diagnosed illnessDatePt^PatientQnPhenXYear of diagnosis of clinician-diagnosed illnessPoint in time (spot)

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.