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Basophilsnfrvitfmanual

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

A laboratory test that manually counts basophils and white blood cells in the vitreous fluid of the eye to help diagnose eye conditions.

Quick summary

{"Measures white blood cells and basophils in the vitreous humor of the eye","Helps diagnose intraocular inflammation, infection, or trauma","Sample is collected by an ophthalmologist through a procedure called vitreous tap","Results assist in differentiating between various eye diseases","Often used when other eye examinations suggest internal eye inflammation"}

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

Key facts at a glance

LOINC
68396-1
Short code
VITROBASO
Synonyms
Basophils NFr Vitf Manual
Category
chemistry
Sample
serum
Container
Sterile microcentrifuge tube (1.5 mL) or sterile cryovial without anticoagulant; for culture add sterile transport medium; smears prepared on glass slides
Units
N/A
Ref low
0
Ref high
1
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
manual-count
CPT
89051 (Cell count, miscellaneous body fluids, with cell count); 85007 (manual differential WBC count) if applicable
SNOMED
397200004 (Vitreous humor sample); 40897000 (Basophil count)
Specimen volume
0.2–0.5 mL of vitreous fluid (minimum 0.1 mL acceptable for direct smear)
Stability
Refrigerate at 2–8 °C and process within 2 hours of collection for optimal cell morphology. For delayed analysis, preserve in cell culture medium or prepare cytospin slides within 4 hours. Do not freeze unfixed specimen.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
2–24 hours
Order
routine

What is this test?

The Basophils/Leukocytes in Vitreous Fluid test is a specialized laboratory examination that counts the number of white blood cells (leukocytes) and basophils in the vitreous humor—the clear, gel-like substance that fills the space between the lens and the retina in the eye. This test is performed manually under a microscope by a trained laboratory technician.

How is the sample collected?

The vitreous fluid sample is collected through a procedure called a vitreous tap or vitrectomy. An ophthalmologist uses a fine needle to extract a small amount of vitreous fluid from the eye. This is typically done under local anesthesia in a clinical or hospital setting. The procedure is considered invasive and is usually performed when other diagnostic methods have not provided sufficient information.

Why is this test performed?

This test is primarily ordered when an ophthalmologist suspects intraocular inflammation (uveitis), infection (endophthalmitis), or trauma to the eye. By analyzing the types and numbers of cells in the vitreous fluid, doctors can determine the cause of eye inflammation and guide appropriate treatment.

Reference range

Basophils are typically absent or present in very low numbers in normal vitreous fluid. Leukocyte (total WBC) count in normal vitreous is generally <10 cells/μL. Results expressed as percentage of basophils relative to total leukocytes and absolute count.N/A

Specimen: serum

Informed consent required for vitreous tap/pars plana aspiration performed by ophthalmologist under local or general anesthesia. No specific fasting required for the laboratory analysis itself; however, follow surgical fasting guidelines if procedure requires sedation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Is the vitreous tap procedure painful?
The procedure is performed under local anesthesia, so you should not feel pain during the collection. You may experience some discomfort or a sensation of pressure in the eye afterward. Your doctor will provide appropriate pain management recommendations.
How long does it take to get results?
Results typically take 1-3 days, as the sample requires manual microscopic examination by a specialized laboratory technician.
Are there any risks to the vitreous tap procedure?
As with any invasive procedure, there are potential risks including infection, bleeding, retinal detachment, or cataract formation. However, when performed by an experienced ophthalmologist, these complications are rare. Your doctor will discuss the risks and benefits with you before the procedure.
Do I need to prepare anything special for this test?
Your ophthalmologist will provide specific instructions. Generally, you should inform them of any medications you are taking, especially blood thinners. You may need to stop wearing contact lenses and arrange for someone to drive you home after the procedure.
  1. 1
    American Academy of Ophthalmology - UveitisSource
  2. 2
    Mayo Clinic - Vitreous TapSource

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