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.

LOINCActiveObservation

LOINC Code 784-9: Erythrocyte mean corpuscular diameter Auto (RBC) [Length]

Name: LOINC Code 784-9: Erythrocyte mean corpuscular diameter Auto (RBC) [Length]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:58.756Z

784-9 is a LOINC code used to identify Erythrocyte mean corpuscular diameter Auto (RBC) [Length] 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 mean corpuscular diameter. It is commonly used with the system or sample type RBC.

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 mean corpuscular diameter. It is commonly used with the system or sample type RBC.

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
Method: Automated count

What it does not mean

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

Key facts

Erythrocyte mean corpuscular diameter [Length] by Automated count
Erythrocyte mean corpuscular diameter
Auto; Automated detection; Average; Avg; DIA; Diam; Discocyte; Elec; Elect; Electr; Erc; Erythrocytes; HEMATOLOGY/CELL COUNTS; Length; MCD; Point in time; QNT; Quan; Quant; Quantitative; Random; RBC; Red blood cell; Red blood cells; Red blood corpuscle; Red blood corpusles; Red cell; Red cells

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

Erythrocyte mean corpuscular diameter Auto (RBC) [Length]Erythrocyte mean corpuscular diameter [Length] by Automated countMCD RBC AutoErythrocyte mean corpuscular diameterHEM/BCRed blood cell mean corpuscular diameter, Red blood cellsLen

Frequently asked questions

Code details

Code784-9

SystemLOINC

Display nameErythrocyte mean corpuscular diameter Auto (RBC) [Length]

DescriptionErythrocyte mean corpuscular diameter

Short nameMCD RBC Auto

ComponentErythrocyte mean corpuscular diameter

PropertyLen

TimingPt

System (specimen)RBC

ScaleQn

MethodAutomated count

ClassHEM/BC

Example unitsum

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0

Last changed2.44

Consumer names

Red blood cell mean corpuscular diameter, Red blood cells

Part names

Erythrocyte mean corpuscular diameterLenPtRBCQnAutomated countLengthPoint in time (spot)Red Blood Cells

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.