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Hemoglobin concentration in packed red blood cells (Hct) measured via automated cell counting

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

This test measures the proportion of red blood cells in your blood, which helps assess red blood cell health and overall blood volume.

Quick summary

["Helps diagnose anemia, polycythemia, or dehydration by evaluating red blood cell density."]

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

Key facts at a glance

LOINC
13508-7
Short code
Hct VFr CSF Spun
Synonyms
Hct VFr CSF Spun
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Ref low
36
Ref high
50
Critical range
18 N/A – 60 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
spun
CPT
85014
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Matters in Blood Health

Hemoglobin concentration in packed red blood cells reflects how efficiently your blood carries oxygen. Abnormal levels may indicate conditions like anemia (low RBCs) or polycythemia (high RBCs).

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in the arm. The sample is processed to separate packed red blood cells from plasma, then analyzed for hemoglobin concentration.

Common Conditions Affecting Results

Low levels may suggest blood loss, iron deficiency, or chronic diseases, while high levels could indicate dehydration, high altitude, or overproduction of red blood cells.

What to Expect Before or After Testing

No special preparation is needed, but inform your provider about medications (e.g., blood thinners) or recent blood donations. Results may take 1–3 days.

Reference range

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

Specimen: csf

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

Hematocrit (Hct) in packed RBCs

Frequently asked questions

What does a high hematocrit mean in my results?
A high hematocrit may signal conditions like dehydration, polycythemia vera, or living at high altitudes. Your provider will consider your symptoms and other test results to determine the cause.
Can diet affect this test?
Dietary changes (e.g., high iron intake) may influence red blood cell production but don’t directly alter hematocrit measurements. Avoid heavy meals 24 hours before testing to ensure accurate results.
Is this test the same as a regular CBC?
Yes, this test is part of a complete blood count (CBC), which also measures hemoglobin, RBC counts, and other blood components. It specifically focuses on the packed RBC fraction’s hemoglobin concentration.
  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