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Whole Blood Hematocrit (Packed Cell Volume)

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

This test measures the proportion of red blood cells in your blood, helping assess red blood cell concentration and potential blood disorders.

Quick summary

["Hematocrit levels can indicate anemia, polycythemia, or dehydration."]

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

Key facts at a glance

LOINC
105921-1
Short code
WBC # Urth Wet Prep
Synonyms
WBC # Urth Wet Prep
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
wet-preparation
CPT
85004
SNOMED
900000000000003002
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 It’s Done

Doctors may order a hematocrit test to diagnose or monitor conditions like anemia (low red blood cells), polycythemia (high red blood cells), or dehydration. It’s also used before surgeries, during pregnancy, or if you have symptoms like fatigue, shortness of breath, or unusual bleeding.

What to Expect

A small blood sample is taken from a vein, usually in your arm. The process is quick and may cause a slight pinch. The blood is then analyzed to determine the percentage of red blood cells.

Normal vs. Abnormal Results

While reference ranges vary by lab, lower than expected levels may suggest anemia or blood loss, while higher levels could indicate dehydration, polycythemia, or other conditions. Your doctor will interpret results in the context of your health.

Common Conditions Linked to Hematocrit

Abnormal hematocrit levels can signal underlying issues such as chronic kidney disease, heart conditions, or certain cancers. It’s important to discuss any symptoms or concerns with your healthcare provider.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Hematocrit (Hct)

Frequently asked questions

How long does it take to get results from this test?
Results are typically available within 1 to 3 business days, depending on lab processing times.
Can I eat or drink anything before this test?
No special preparation is needed. However, avoid alcohol for 24 hours before the test if instructed by your doctor.
Is there any risk or discomfort associated with this test?
The most common discomfort is a minor bruise or slight pain at the needle site. Rarely, there may be a small risk of infection or excessive bleeding, but these are uncommon.
  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