LOINCActiveObservation

LOINC Code 46639-1: Primary diagnosis [RFC]

46639-1 is a LOINC code used to identify Primary diagnosis [RFC] 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 Diagnosis.primary. 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 Diagnosis.primary. 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
  • Method: RFC assessment

What it does not mean

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

Key facts

  • Primary diagnosis [RFC]
  • Diagnosis.primary
  • Dx; Dx.primary; Impression; Impression/interpretation of study; Impressions; Interp; Interpretation; Narrative; Point in time; Random; Report; Residual Functional Capacity; RFCA; Survey; Survey.RFC

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

Primary diagnosis [RFC]Diagnosis.primarySURVEY.RFCImpPt^PatientNar

Frequently asked questions

Code details

Code46639-1
SystemLOINC
Display namePrimary diagnosis [RFC]
DescriptionDiagnosis.primary
ComponentDiagnosis.primary
PropertyImp
TimingPt
System (specimen)^Patient
ScaleNar
MethodRFC assessment
ClassSURVEY.RFC
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.19
Last changed2.44

Part names

Diagnosis.primaryImpPt^PatientNarRFC assessmentImpression/interpretation of studyPoint 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.

LOINC Code 46639-1 | HealthAssure