LOINCActiveObservation

LOINC Code 16640-5: Coccidioides reaction wheal (Skin) [Diam]

16640-5 is a LOINC code used to identify Coccidioides reaction wheal (Skin) [Diam] 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 Coccidioides reaction wheal. It is commonly used with the system or sample type Skin.

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 Coccidioides reaction wheal. It is commonly used with the system or sample type Skin.

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

  • Coccidioides reaction wheal [Diameter]
  • Coccidioides reaction wheal
  • Coccidioides wheal; Dermatologic; Diameter; Epidermis; Integument; Point in time; QNT; Quan; Quant; Quantitative; Random; React; Rx wheal; Rxn; San Joaquin Valley fever; Skin test; SKIN TESTS; Skn; Valley fever

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

Coccidioides reaction wheal (Skin) [Diam]Coccidioides reaction wheal [Diameter]Coccidioides wheal DiamCoccidioides reaction whealCHALSKINCoccidioides reaction wheal, SkinDiam

Frequently asked questions

Code details

Code16640-5
SystemLOINC
Display nameCoccidioides reaction wheal (Skin) [Diam]
DescriptionCoccidioides reaction wheal
Short nameCoccidioides wheal Diam
ComponentCoccidioides reaction wheal
PropertyDiam
TimingPt
System (specimen)Skin
ScaleQn
ClassCHALSKIN
Example unitsmm
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0l
Last changed2.42

Consumer names

Coccidioides reaction wheal, Skin

Part names

Coccidioides reaction whealDiamPtSkinQnDiameterPoint 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 16640-5 | HealthAssure