Red Blood Cell Count, Manual Method
A red blood cell (RBC) count measures the number of red blood cells in a sample of blood. The manual method means the cells are counted by a trained technologist using a microscope rather than by an automated instrument.
["A manual RBC count provides a direct count of red blood cells and is often used to check or confirm results from automated analyzers."]
Key facts at a glance
- LOINC
- 793-0
- Short code
- RBC # Plr Manual
- Synonyms
- RBC # Plr Manual
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Ref low
- 4.2
- Ref high
- 5.9
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- manual-count
- CPT
- 85041
- SNOMED
- 900000000000003001
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
Red blood cells carry oxygen from your lungs to the rest of your body. This test counts how many red blood cells are present in a known volume of blood. The manual method uses a specially prepared counting chamber viewed under a microscope, and a technologist tallies the cells directly.
Why a Manual Count May Be Done
Automated blood analyzers usually perform RBC counts quickly. A manual count may be requested when automated results are unusual, when the sample is difficult to analyze, or when a second, independent count is needed to confirm a finding. It can also be used in settings where automated equipment is not available.
How the Sample Is Collected
A small blood sample is typically drawn from a vein in your arm, or sometimes from a fingerstick. The sample is diluted in a precise way and placed in a counting chamber so the cells can be seen and counted under a microscope.
What the Results Can Mean
A red blood cell count that is lower than expected may be seen with anemia or blood loss, while a higher count may occur with certain lung, heart, or bone marrow conditions. Results are interpreted together with other tests such as hemoglobin, hematocrit, and red cell indices, and always in the context of your symptoms and history.
Reference range
Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The manual RBC count is a foundational hematology measurement. It helps evaluate the number of circulating red blood cells and supports the diagnosis and monitoring of anemia, polycythemia, and other blood disorders. Because results depend on technique and sample quality, manual counts are often compared with automated results and reviewed alongside the broader blood count panel.
Short name
Manual RBC Count
Frequently asked questions
Is a manual RBC count different from an automated one?
Do I need to fast before this test?
Can I get the results right away?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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