LOINCActiveObservation

LOINC Code 81665-2: IV number [Identifier]

81665-2 is a LOINC code used to identify IV number [Identifier] 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 IV number. 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 IV number. 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

What it does not mean

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

Key facts

  • IV number [Identifier]
  • IV number
  • The IV catheter number identifies a specific IV catheter in cases where a patient has more than one IV at a given point in time.
  • Ident; Identifier; IO; IO.TUBE; IV #; No; Nominal; Num; Point in time; Random

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

IV number [Identifier]IV #IV numberIO.TUBEIDPt^Patient

Frequently asked questions

Code details

Code81665-2
SystemLOINC
Display nameIV number [Identifier]
DescriptionIV number
Short nameIV #
ComponentIV number
PropertyID
TimingPt
System (specimen)^Patient
ScaleNom
ClassIO.TUBE
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.56
Last changed2.56

Part names

IV numberIDPt^PatientNomIdentifierPoint 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 81665-2 | HealthAssure