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.

LOINCActive

LOINC Code 63641-5: Do, or did, you smoke more frequently during the first hours after waking than during the rest of the day [FTND]

Name: LOINC Code 63641-5: Do, or did, you smoke more frequently during the first hours after waking than during the rest of the day [FTND]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:42.802Z

63641-5 is a LOINC code used to identify Do, or did, you smoke more frequently during the first hours after waking than during the rest of the day [FTND] 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 Do, or did, you smoke more frequently during the first Hs after waking than during the rest of the day. 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 Do, or did, you smoke more frequently during the first Hs after waking than during the rest of the day. 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
Method: FTND

What it does not mean

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

Key facts

Do, or did, you smoke more frequently during the first hours after waking than during the rest of the day [FTND]
Do, or did, you smoke more frequently during the first Hs after waking than during the rest of the day
Finding; Findings; Ordinal; PhenX; Point in time; QL; Qual; Qualitative; Random; Screen; Smoke more 1st Hs

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

Do, or did, you smoke more frequently during the first hours after waking than during the rest of the day [FTND]Smoke more 1st Hs FTNDDo, or did, you smoke more frequently during the first Hs after waking than during the rest of the dayPHENXFindPt^Patient

Frequently asked questions

Code details

Code63641-5

SystemLOINC

Display nameDo, or did, you smoke more frequently during the first hours after waking than during the rest of the day [FTND]

DescriptionDo, or did, you smoke more frequently during the first Hs after waking than during the rest of the day

Short nameSmoke more 1st Hs FTND

ComponentDo, or did, you smoke more frequently during the first Hs after waking than during the rest of the day

PropertyFind

TimingPt

System (specimen)^Patient

ScaleOrd

MethodFTND

ClassPHENX

StatusACTIVE

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.36

Last changed2.65

Part names

Do, or did, you smoke more frequently during the first Hs after waking than during the rest of the dayFindPt^PatientOrdFTNDDo, or did, you smoke more frequently during the first hours after waking than during the rest of the dayFindingPoint 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.