What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveBoth

LOINC Code 18204-8: Caffeine renal clearance (24H U+S/P) [Vol/Time]

Name: LOINC Code 18204-8: Caffeine renal clearance (24H U+S/P) [Vol/Time]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T11:17:27.586Z

18204-8 is a LOINC code used to identify Caffeine renal clearance (24H U+S/P) [Vol/Time] 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 Caffeine renal clearance. It is commonly used with the system or sample type Urine+Ser/Plas.

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 Caffeine renal clearance. It is commonly used with the system or sample type Urine+Ser/Plas.

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: Both

What it does not mean

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

Key facts

Caffeine renal clearance in 24 hour Urine and Serum or Plasma
Caffeine renal clearance
1 day; 24 hours; 24HR; CAFFN; Cl; Clear; Clearanc; Clearances; Clr; DRUG/TOXICOLOGY; Drugs; Flow; Kidney; Pl; Plasma; Plsm; QNT; Quan; Quant; Quantitative; SerP; SerPl; SerPlas; Serum; Serum or plasma; SR; UA; UR; Ur+SerPl; Urn; Volume rate; vRate

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

Caffeine renal clearance (24H U+S/P) [Vol/Time]Caffeine renal clearance in 24 hour Urine and Serum or PlasmaCaffeine Cl 24h Ur+SerPl-vRateCaffeine renal clearanceDRUG/TOXCaffeine renal clearance, Urine+BloodVRat

Frequently asked questions

Code details

Code18204-8

SystemLOINC

Display nameCaffeine renal clearance (24H U+S/P) [Vol/Time]

DescriptionCaffeine renal clearance

Short nameCaffeine Cl 24h Ur+SerPl-vRate

ComponentCaffeine renal clearance

PropertyVRat

Timing24H

System (specimen)Urine+Ser/Plas

ScaleQn

ClassDRUG/TOX

Example unitsmL/min

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0l

Last changed2.66

Consumer names

Caffeine renal clearance, Urine+Blood

Part names

Caffeine renal clearanceVRat24HUrine+Ser/PlasQnVolume Rate24 hoursUrine and Serum or Plasma

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.