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 51790-4: RBC casts LM.HPF (Urine sed) [#/Area]

Name: LOINC Code 51790-4: RBC casts LM.HPF (Urine sed) [#/Area]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:35.013Z

51790-4 is a LOINC code used to identify RBC casts LM.HPF (Urine sed) [#/Area] 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 Erythrocyte casts. It is commonly used with the system or sample type Urine sed.

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 Erythrocyte casts. It is commonly used with the system or sample type Urine sed.

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
Method: Microscopy.light.HPF

What it does not mean

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

Key facts

RBC casts [#/area] in Urine sediment by Microscopy high power field
Erythrocyte casts
#/area; Cast; Discocyte; Erc; Erythrocytes; Kidney; LM; Micro; Micros; Microscopic; Nephrology; Number areic; Point in time; QNT; Quan; Quant; Quantitative; Random; RBC; RBC Casts; Red blood cell; Red blood cells; Red blood corpuscle; Red blood corpusles; Red cell; Red cells; Renal; UA; UR; URINALYSIS; Urine sediment; Urn; UrnS

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

RBC casts LM.HPF (Urine sed) [#/Area]RBC casts [#/area] in Urine sediment by Microscopy high power fieldRBC Casts #/area UrnS HPFErythrocyte castsUARed blood cell casts, Urine sedimentNaric

Frequently asked questions

Code details

Code51790-4

SystemLOINC

Display nameRBC casts LM.HPF (Urine sed) [#/Area]

DescriptionErythrocyte casts

Short nameRBC Casts #/area UrnS HPF

ComponentErythrocyte casts

PropertyNaric

TimingPt

System (specimen)Urine sed

ScaleQn

MethodMicroscopy.light.HPF

ClassUA

Example units/HPF

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.24

Last changed2.73

Consumer names

Red blood cell casts, Urine sediment

Part names

Erythrocyte castsNaricPtUrine sedQnMicroscopy.light.HPFRBC castsNumber Areic (per area)Point in time (spot)Urine sedimentMicroscopy high power field

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.