🔬 What is the Test?
The AFB (Acid-Fast Bacilli) Ziehl-Neelsen Stain Test is a microscopic staining method used to detect Mycobacterium tuberculosis (TB) and non-tuberculous mycobacteria (NTM) in clinical samples. The Ziehl-Neelsen (ZN) stain highlights acid-fast bacteria, making them easier to identify under a microscope.
📊 Normal Ranges:
Negative → No AFB detected (TB or NTM infection unlikely).
Positive → AFB detected (further testing required for confirmation and drug resistance profiling).
(Results vary based on sample quality and bacterial load.)
🎯 Purpose of the Test:
✅ Rapid screening for tuberculosis (TB) and mycobacterial infections
✅ Helps detect pulmonary and extrapulmonary TB
✅ Used for early diagnosis and treatment initiation
✅ Assists in monitoring TB treatment progress
🩺 When is it Recommended?
🔹 Patients with TB symptoms (persistent cough, fever, weight loss, night sweats)
🔹 Individuals at high risk of TB exposure
🔹 To confirm suspected cases of TB and NTM infections
🔹 To track TB treatment effectiveness
📝 How is the Test Done?
A sputum, CSF, urine, or tissue sample is collected.
The sample is spread onto a glass slide and heat-fixed.
It is stained using carbol fuchsin, acid-alcohol, and methylene blue.
Under a microscope, acid-fast bacilli (AFB) appear bright red against a blue background.
Results are typically available within a few hours to a day.
⚠️ What Do Abnormal Results Mean?
📉 Negative → No AFB detected (does not rule out TB; culture may be needed).
📈 Positive → AFB detected (further testing required for TB confirmation and drug susceptibility).
🔍 Infographic Design Idea:
Medical-themed colors (blue, red, and white)
Illustration of red-stained TB bacteria under a microscope
Flowchart explaining the Ziehl-Neelsen staining process
Table summarizing positive vs. negative results