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.

LOINCActiveObservation

LOINC Code 105509-4: Age at which you began taking medicine for this

Name: LOINC Code 105509-4: Age at which you began taking medicine for this
Creator: HealthAssure Clinical Team
Published: 2026-05-21T11:17:19.135Z

105509-4 is a LOINC code used to identify Age at which you began taking medicine for this 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 Age at which you began taking medicine for this. 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 Age at which you began taking medicine for this. 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: ACTIVE
Order vs observation: Observation

What it does not mean

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

Key facts

Age at which you began taking medicine for this
Age began taking meds; PhenX; Point in time; 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

Age at which you began taking medicine for thisAge began taking medsPHENXTimePt^PatientQn

Frequently asked questions

Code details

Code105509-4

SystemLOINC

Display nameAge at which you began taking medicine for this

Short nameAge began taking meds

ComponentAge at which you began taking medicine for this

PropertyTime

TimingPt

System (specimen)^Patient

ScaleQn

ClassPHENX

Example unitsa

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.78

Last changed2.78

Part names

Age at which you began taking medicine for thisTimePt^PatientQnTime (e.g. seconds)Point 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.