LOINCActiveBoth

LOINC Code 12310-9: Phenytoin Ql (U)

12310-9 is a LOINC code used to identify Phenytoin Ql (U) 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 Phenytoin. It is commonly used with the system or sample type Urine.

Reviewed by HealthAssure Clinical TeamUpdated 25 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 Phenytoin. It is commonly used with the system or sample type Urine.

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

  • Phenytoin [Presence] in Urine
  • Phenytoin
  • DI-HYDAN; Dilantin; Dilj; Diphenylhydantoin; DPH; DRUG/TOXICOLOGY; Drugs; Epanutin; Fenantoin; Lehydan; Ordinal; Phenhydan; PHYT; Point in time; PR; QL; Qual; Qualitative; Random; Screen; Sinergina; UA; UR; Urn; Zentropil

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

Phenytoin Ql (U)Phenytoin [Presence] in UrinePhenytoin Ur QlPhenytoinDRUG/TOXPhenytoin, UrinePrThr

Frequently asked questions

Code details

Code12310-9
SystemLOINC
Display namePhenytoin Ql (U)
DescriptionPhenytoin
Short namePhenytoin Ur Ql
ComponentPhenytoin
PropertyPrThr
TimingPt
System (specimen)Urine
ScaleOrd
ClassDRUG/TOX
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0j-a
Last changed2.73

Consumer names

Phenytoin, Urine

Part names

PhenytoinPrThrPtUrineOrdPresence or ThresholdPoint 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 12310-9 | HealthAssure