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Human Leukocyte Antigen-DR (HLA-DR) Expression on Blast Cells — Flow Cytometry

Published: August 9, 2026Updated: August 16, 2026

Measures HLA-DR protein on blast cells by flow cytometry to help characterize abnormal cells, often during evaluation of leukemia.

Quick summary

["This test helps determine whether blast cells carry the HLA-DR marker and can support the classification of leukemia."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
107054-9
Short code
Blasts.HLA-DR+ NFr Spec FC
Synonyms
Blasts.HLA-DR+ NFr Spec FC
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
0.1 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
84484
SNOMED
302774002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This test measures human leukocyte antigen-DR, or HLA-DR, on blast cells. Blast cells are immature cells that normally develop into blood cells, and flow cytometry can detect the presence and amount of this cell-surface marker.

Why might I need this test?

HLA-DR testing may be used when an abnormal blood or bone marrow sample suggests leukemia or another blood-cell disorder. The result helps laboratory specialists identify and classify the abnormal cells.

How is the test performed?

A laboratory cell sample, commonly blood or bone marrow, is analyzed using flow cytometry. Fluorescent-labeled antibodies bind HLA-DR, allowing the instrument to measure the marker on individual blast cells.

How do I prepare for the test?

No special preparation is usually required beyond following the laboratory's collection instructions. Tell your clinician about recent chemotherapy, stem-cell transplantation, or blood transfusion because these may affect the results.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HLA-DR on blast cells

Frequently asked questions

What does HLA-DR stand for?
HLA-DR stands for human leukocyte antigen-DR. It is a protein found on the surface of certain immune cells.
Are blast cells always cancerous?
No. Blast cells can occasionally be found outside the bone marrow, so findings must be interpreted with the clinical context and other laboratory results.
Does this test replace a bone marrow biopsy?
No. Flow cytometry characterizes cell markers, while biopsy or other testing may still be needed to assess the structure of the marrow and confirm a diagnosis.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy