LOINCActiveObservation

LOINC Code 1648-5: Tuberculosis reaction wheal 3 days post 5 TU intradermal (Skin) [Diam]

1648-5 is a LOINC code used to identify Tuberculosis reaction wheal 3 days post 5 TU intradermal (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 Tuberculosis reaction wheal^3D post 5 TU ID. 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 Tuberculosis reaction wheal^3D post 5 TU ID. 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

  • Tuberculosis reaction wheal [Diameter] --3 days post 5 TU intradermal
  • Tuberculosis reaction wheal^3D post 5 TU ID
  • 3D p 5 TU; After; Dermatologic; Diameter; Epidermis; Identifier; Integument; Intermediate strength PPD; Intradermal; Point in time; PPD; PST; Purified protein derivative skin test; Purified protein derivative test; QNT; Quan; Quant; Quantitative; Random; React; Rx wheal; Rxn; Skin test; SKIN TESTS; Skn; TB; TB skin test; TB Wheal; TST; Tubeculin Units

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

Tuberculosis reaction wheal 3 days post 5 TU intradermal (Skin) [Diam]Tuberculosis reaction wheal [Diameter] --3 days post 5 TU intradermalTB Wheal 3D p 5 TU DiamTuberculosis reaction wheal^3D post 5 TU IDCHALSKINTuberculosis reaction wheal 3 days after 5 TU Intradermal, SkinDiam

Frequently asked questions

Code details

Code1648-5
SystemLOINC
Display nameTuberculosis reaction wheal 3 days post 5 TU intradermal (Skin) [Diam]
DescriptionTuberculosis reaction wheal^3D post 5 TU ID
Short nameTB Wheal 3D p 5 TU Diam
ComponentTuberculosis reaction wheal^3D post 5 TU ID
PropertyDiam
TimingPt
System (specimen)Skin
ScaleQn
ClassCHALSKIN
Example unitsmm
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0
Last changed2.73

Consumer names

Tuberculosis reaction wheal 3 days after 5 TU Intradermal, Skin

Part names

Tuberculosis reaction wheal^3D post 5 TU IDDiamPtSkinQnDiameterPoint 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.