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 49498-9: WBC Estimate (Bld) [#/Vol]

Name: LOINC Code 49498-9: WBC Estimate (Bld) [#/Vol]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:33.941Z

49498-9 is a LOINC code used to identify WBC Estimate (Bld) [#/Vol] 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 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 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: Estimate

What it does not mean

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

Key facts

Leukocytes [#/volume] in Blood by Estimate

Leukocytes

In the Hematology world estimated cell counts have existed for many moons and they are reported either qualitatively or quantitatively and done strictly by blood smear review. Smear Estimated WBC and Platelet counts that aren't just reported as reduced/adequate/many that are actually estimated as a numeric result like an estimate of 4 K/cumm for WBC or 400 K/cumm for platelets. Like doing a retic count by counting so many fields on the smear type of estimate. This WBC estimate count is a manual quantitative count. We report a number. See laboratory procedureA. WBC Count Smear Estimate: 1. Use the 50X oil immersion objective. 2. Count the number of both intact and disrupted WBCs in each of 10 microscopic fields in different areas of the slide where RBCs slightly overlap. Divide the total number by 10 to establish the mean number of WBCs/field and multiply this mean by 3,000 to get the estimated WBC count/mm³. Do not round off the mean, e.g., if the mean is 5.7 do not round off to 6 but leave the figure at one place past the decimal point for greater accuracy. 3. If the quantitative WBC count is <25,000, the estimated smear count should be within 1,500 cells of this figure. Estimate counts are less reliable at >25,000 cells/mm³. III. REFERENCES: A. A Color Atlas and Instruction Manual of Peripheral Blood Cells Morphology, by Barbara H. O'Connor, 1984, p. 20. B. Principles and Procedures, Barbara A. Brown, 6th Edition, 1993, p. 104.

#; ABS; absolute; absolutes; Blood; Cnt; Count; Count/volume; CT; estimation; HEMATOLOGY/CELL COUNTS; Leuc; Leuk; Leukocyte; Lkcs; Number concentration; Number Concentration (count/vol); 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

WBC Estimate (Bld) [#/Vol]Leukocytes [#/volume] in Blood by EstimateWBC # Bld EstLeukocytesHEM/BCWhite blood cell (WBC) count, BloodNCnc

Frequently asked questions

Code details

Code49498-9

SystemLOINC

Display nameWBC Estimate (Bld) [#/Vol]

DescriptionLeukocytes

Short nameWBC # Bld Est

ComponentLeukocytes

PropertyNCnc

TimingPt

System (specimen)Bld

ScaleQn

MethodEstimate

ClassHEM/BC

Example units10*3/mm3

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.22

Last changed2.73

Consumer names

White blood cell (WBC) count, Blood

Part names

LeukocytesNCncPtBldQnEstimateNumber ConcentrationPoint 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.