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Hemoglobin concentration (whole blood)

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

This test measures the amount of hemoglobin in your red blood cells, which helps assess your body’s ability to carry oxygen.

Quick summary

["Hemoglobin levels help diagnose and monitor conditions related to anemia or blood disorders."]

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

Key facts at a glance

LOINC
104876-8
Short code
Hct 1h p Glc VFr Bld
Synonyms
Hct 1h p Glc VFr Bld
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
36
Ref high
50
Critical range
18 N/A – 60 N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
CPT
85014
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?

Your healthcare provider may order this test to check for anemia (low hemoglobin), polycythemia (high hemoglobin), or other blood-related conditions. It’s also used during pregnancy, before surgery, or if you have symptoms like fatigue, pale skin, or shortness of breath.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw a blood sample. The process usually takes a few minutes, and you may feel a brief pinch. If you’re pregnant or have a blood disorder, let your provider know.

What the Results Mean

Hemoglobin levels vary by age, sex, and health status. Your results will be compared to standard ranges provided by your lab. Low levels may indicate anemia, while very high levels could suggest conditions like dehydration or polycythemia.

Common Conditions Affecting Results

Factors like pregnancy, heavy menstrual bleeding, chronic illness, or certain medications can influence hemoglobin levels. Blood loss from injuries or infections may also lead to lower levels, while smoking or high altitude can sometimes raise them.

Reference range

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

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Hemoglobin (Hb) Level

Frequently asked questions

What questions might you have about this test?
This test is typically done to check for anemia or blood disorders, but it can also be part of routine health screenings or monitoring for conditions like heart disease or kidney problems. If your results are outside the normal range, further testing may be needed to determine the cause.
How often should I get this test?
The frequency depends on your health status. For example, pregnant women may get it monthly, while people with chronic conditions might need it more often. Your healthcare provider will determine the best schedule for you.
Can I eat or drink before this test?
You can eat and drink normally before the test, as it doesn’t require fasting. However, if you’re taking certain medications that affect blood levels, let your provider know before scheduling it.
  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