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 55377-6: Mononuclear cells immature/Leukocytes Manual cnt (Bld)

Name: LOINC Code 55377-6: Mononuclear cells immature/Leukocytes Manual cnt (Bld)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:37.144Z

55377-6 is a LOINC code used to identify Mononuclear cells immature/Leukocytes Manual cnt (Bld) 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 Mononuclear cells.immature/Leukocytes. It is commonly used with the system or sample type Bld.

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 Mononuclear cells.immature/Leukocytes. It is commonly used with the system or sample type Bld.

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: Manual count

What it does not mean

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

Key facts

Mononuclear cells immature/Leukocytes in Blood by Manual count
Mononuclear cells.immature/Leukocytes
Blood; Cell; Cellularity; HEMATOLOGY/CELL COUNTS; Imm; Immat; Immature mononuc; Leuc; Leuk; Leukocyte; Lkcs; Manl; Mononuc; Mononuc Cells; Number Fraction; Percent; Point in time; QNT; Quan; Quant; Quantitative; Random; WB; WBC; WBCs; White blood cell; White blood cells; Whole blood

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

Mononuclear cells immature/Leukocytes Manual cnt (Bld)Mononuclear cells immature/Leukocytes in Blood by Manual countImmature mononuc NFr Bld ManualMononuclear cells.immature/LeukocytesHEM/BCMononuclear cells immature/White Blood Cells, BloodNFr

Frequently asked questions

Code details

Code55377-6

SystemLOINC

Display nameMononuclear cells immature/Leukocytes Manual cnt (Bld)

DescriptionMononuclear cells.immature/Leukocytes

Short nameImmature mononuc NFr Bld Manual

ComponentMononuclear cells.immature/Leukocytes

PropertyNFr

TimingPt

System (specimen)Bld

ScaleQn

MethodManual count

ClassHEM/BC

Example units%

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.27

Last changed2.79

Consumer names

Mononuclear cells immature/White Blood Cells, Blood

Part names

Mononuclear cells.immature/LeukocytesNFrPtBldQnManual countNumber FractionPoint in time (spot)Blood

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.