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Hemoglobin concentration (whole blood) by mass concentration measurement

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of hemoglobin in your blood, which carries oxygen to your body’s tissues. Hemoglobin levels help doctors assess your red blood cell health and overall blood health.

Quick summary

["Hemoglobin levels indicate whether you may have anemia or other blood-related conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
104875-0
Short code
Hct 30M p Glc VFr Bld
Synonyms
Hct 30M p Glc VFr Bld
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
36
Ref high
50
Critical range
20 N/A – 400 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
85014
SNOMED
302346007
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

Why Is This Test Done?

Doctors order hemoglobin tests to diagnose or monitor conditions such as anemia (low red blood cell count), blood loss, or other blood disorders. It may also be checked during routine health screenings or before surgeries.

What Does a Low or High Hemoglobin Level Mean?

Low hemoglobin levels (anemia) may cause fatigue, weakness, or pale skin. High levels can sometimes indicate conditions like polycythemia (too many red blood cells) or dehydration. Your doctor will interpret results in the context of your symptoms and medical history.

How Is This Test Performed?

A small blood sample is drawn from a vein in your arm. The sample is sent to a lab where hemoglobin concentration is measured using automated equipment. No special preparation is needed.

What Are Common Reasons for Testing?

Common reasons include checking for anemia, evaluating chronic diseases (like kidney disease or heart failure), diagnosing unexplained fatigue, or assessing blood health before procedures.

Reference range

Adult males: 38-50%; Females: 36-44%N/A

Specimen: serum

Take your thyroid medication after the blood draw if applicable. No fasting required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Hemoglobin (Hb) level

Frequently asked questions

What does a hemoglobin test measure exactly?
It measures the mass concentration of hemoglobin in your red blood cells, which reflects your blood’s oxygen-carrying capacity.
Can diet affect hemoglobin test results?
Yes, certain foods (like iron-rich foods) or supplements can influence hemoglobin levels. Avoiding heavy meals 12 hours before testing helps ensure accurate results.
Is a hemoglobin test painful?
A small needle is used to draw blood, which may cause a brief sting. Most people experience minimal discomfort, and the site may bruise slightly afterward.
  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 17, 2026. · Read our editorial policy