LOINC

LOINC Code 66100-9: Are your symptoms worse at night [PhenX]

66100-9 is a LOINC code used to identify Are your symptoms worse at night [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 Are your symptoms worse at night. 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 Are your symptoms worse at night. 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

  • Are your symptoms worse at night [PhenX]
  • Are your symptoms worse at night
  • Finding; Findings; Ordinal; Point in time; QL; Qual; Qualitative; Random; Screen; Sx

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

Are your symptoms worse at night [PhenX]Symptoms worse at night PhenXAre your symptoms worse at nightPHENXFindPt^Patient

Frequently asked questions

Code details

Code66100-9
SystemLOINC
Display nameAre your symptoms worse at night [PhenX]
DescriptionAre your symptoms worse at night
Short nameSymptoms worse at night PhenX
ComponentAre your symptoms worse at night
PropertyFind
TimingPt
System (specimen)^Patient
ScaleOrd
MethodPhenX
ClassPHENX
StatusTRIAL

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.36
Last changed2.65

Part names

Are your symptoms worse at nightFindPt^PatientOrdPhenXFindingPoint 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.