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Basophilsplrmanual

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

This test counts basophils (a type of white blood cell) in fluid collected from around the lungs through a manual microscopic examination.

Quick summary

{"Basophils are white blood cells that play a role in allergic reactions and inflammation","This test examines fluid from the pleural space (area around the lungs)","Results help doctors diagnose the cause of fluid buildup in the chest","Abnormal basophil counts may indicate infection, cancer, or other conditions","The test is performed by examining the fluid under a microscope"}

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

Key facts at a glance

LOINC
68394-6
Short code
BASO-PL
Synonyms
Basophils # Plr Manual
Category
chemistry
Sample
fluid
Container
Sterile, leak-proof collection container (e.g., sterile screw-capped tube or vacuum container) without anticoagulant for cell count, or EDTA tube if anticoagulation is required
Units
N/A
Ref low
0
Ref high
0
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
manual-count
CPT
89051
SNOMED
127250006
Specimen volume
Minimum 2 mL of pleural fluid; ideally 10-20 mL for complete cell count analysis
Stability
Room temperature: 1-2 hours for optimal cell morphology; refrigerated (2-8°C): up to 24 hours; smears should be prepared within 1 hour of collection to prevent cell deterioration
Hemolysis max
300
TAT
1–4 hours
Order
routine

What is this test?

The Pleural Fluid Basophil Count is a laboratory test that counts the number of basophils in a sample of pleural fluid. Basophils are a type of white blood cell that are part of your immune system. They help defend your body against infections and play a role in allergic reactions. This test is performed manually by a technician who examines the fluid sample under a microscope.

Why is this test performed?

Your doctor may order this test if you have fluid accumulating in the pleural space (the area around your lungs), a condition called pleural effusion. The test helps determine the cause of the fluid buildup by examining the types of cells present in the fluid. It can help differentiate between different causes such as infection, cancer, heart failure, or other conditions.

How is the sample collected?

Pleural fluid is collected through a procedure called thoracentesis. During this procedure, a doctor inserts a thin needle through the chest wall and into the pleural space to withdraw excess fluid. The area will be cleaned and numbed with local anesthetic to minimize discomfort. The fluid sample is then sent to a laboratory for analysis.

What should I expect during the procedure?

Before the procedure, your doctor may order a chest X-ray or ultrasound to locate the fluid. During thoracentesis, you will sit upright and lean forward on a table. The doctor will clean your back and inject a numbing medicine. You may feel pressure as the needle is inserted, but the procedure is generally well-tolerated. The procedure usually takes 15-30 minutes, and you may have a chest X-ray afterward to check for any complications.

Reference range

Normally absent or very rare in pleural fluid; basophils typically comprise 0% of nucleated cells in healthy individualsN/A

Specimen: fluid

No specific patient preparation required prior to thoracentesis; however, fasting is not mandatory for this test

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Is the thoracentesis procedure painful?
You will receive local anesthesia to numb the area, so you should not feel pain during the procedure. You may feel some pressure or discomfort when the needle is inserted. After the procedure, you may feel some soreness at the insertion site.
How long does it take to get results?
Results are typically available within 1-2 days, depending on the laboratory. Your doctor will discuss the results with you during a follow-up appointment.
What do high basophil counts mean?
Elevated basophils in pleural fluid may suggest an allergic or inflammatory process. However, the test results must be interpreted in context with other findings. Your doctor will consider your symptoms, medical history, and other test results to determine the significance of the findings.
Are there any risks associated with this test?
Thoracentesis is generally safe, but like any procedure, it carries some risks. These may include pneumothorax (air in the chest cavity), bleeding, infection, or rare reactions to the anesthesia. Your doctor will discuss these risks with you before the procedure.
Do I need to prepare for this test?
Your doctor will provide specific instructions. You may need to stop taking certain medications like blood thinners before the procedure. Inform your doctor about any allergies, medications you are taking, and if you have any bleeding disorders.
  1. 1
    Pleural Effusion: Diagnosis and ManagementSource
  2. 2
    Mayo Clinic - ThoracentesisSource
  3. 3
    UpToDate - Pleural fluid analysisSource

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