Understanding Your Laboratory Test: Purpose, Procedure, and Preparation
A blood test that measures the number of basophils, a type of white blood cell, in your blood sample.
{"Basophils are white blood cells that help your body fight infections and respond to allergens","This test helps doctors evaluate your immune system and diagnose certain conditions","Results are often reviewed alongside other white blood cell counts for a complete picture"}
Key facts at a glance
- LOINC
- 23823-8
- Short code
- BASOMAN
- Synonyms
- Basophils NFr Spec Manual
- Category
- chemistry
- Sample
- serum
- Container
- Lavender-top (EDTA) vacutainer tube; sterile blood collection container
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- manual-count
- CPT
- 85009 (Manual blood count, differential WBC count with buffy coat, when performed); 85007 (Blood count; manual differential WBC count)
- SNOMED
- 612-6 | Basophils/Leukocytes [#/volume] in Blood by Manual count; 26436-6 | Leukocytes [#/volume] in Blood
- Specimen volume
- 3-5 mL whole blood (minimum 1 mL for pediatric samples)
- Stability
- Room temperature: 1-2 hours for optimal morphology; refrigerated (2-8°C): up to 4-6 hours. Smears should be prepared within 1 hour of collection for best basophil identification
- Hemolysis max
- 100
- Lipemia max
- 200
- Icterus max
- 50
- TAT
- 2–8 hours
- Order
- routine
This test is a laboratory analysis that helps your healthcare provider check how well your body is working, screen for certain health conditions, or monitor a condition you already have. By examining a sample in a lab, your care team gathers important information that guides diagnosis and treatment decisions.
The basophil count test measures the percentage or absolute number of basophils in your blood. Basophils are the least common type of white blood cell, but they play an important role in your immune system. They contain histamine and other chemicals that are released during allergic reactions and help defend your body against parasites.
How the test is performed depends on the type of sample needed. Most laboratory tests require a small blood sample drawn from a vein in your arm with a fine needle, while others use a urine, saliva, or swab sample. A trained technician collects the sample, which is then sent to the lab for analysis. The procedure is usually quick and causes only mild, brief discomfort.
A healthcare professional will draw a small blood sample from a vein in your arm. The sample is then examined under a microscope by a lab technician who manually counts the basophils. This is called a manual differential count. The test may be part of a complete blood count (CBC) with differential, which examines all types of white blood cells.
Preparation depends on the specific test your provider ordered. Some tests require fasting for 8 to 12 hours, so you may be asked to avoid food and drinks other than water beforehand. Avoid alcohol, and tell your care team about all medications, vitamins, and supplements you take, since some can affect results. Your provider will give you exact instructions.
No special preparation is typically needed. You can eat and drink normally before the test. However, always follow any specific instructions given by your healthcare provider. Certain medications, such as steroids or antihistamines, may affect your basophil count, so inform your doctor about all medications you are taking.
Reference range
Basophils: 0-1% of total leukocytes; 0-0.1 x 10^3/µL (0-100 cells/µL). Leukocytes (WBC): 4.0-11.0 x 10^3/µLN/A
No fasting required. Patient should be in a seated or resting position for at least 15 minutes before blood collection. Avoid strenuous exercise prior to sampling as it may transiently alter leukocyte counts. Inform provider of any recent infections, medications (especially corticosteroids), or allergies
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated basophil levels (basophilia) may indicate allergic reactions, parasitic infections, certain cancers (such as leukemia), chronic inflammation, or autoimmune conditions. Low basophil levels (basopenia) are less common and may occur during severe allergic reactions, hyperthyroidism, or as a side effect of certain medications like corticosteroids.
Basophil counts alone rarely provide a diagnosis. Doctors interpret these results together with other white blood cell counts, your symptoms, and medical history to understand your overall health status.
Frequently asked questions
What are normal basophil levels?
Why would my doctor order this test?
Does a high basophil count mean I have cancer?
Is the test painful?
Sources
- 1
- 2
- 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 10, 2026. · Read our editorial policy