Quick answer
The Sputum AFB Test costs ₹450 at Live Line Health Care. A stained sputum smear is checked under the microscope for acid-fast bacilli, a simple first test for infectious lung TB and for following treatment. No fasting is needed. It uses a sputum sample and the report is usually ready within 24 hours.
Also known as: Sputum for AFB, AFB Smear, Acid Fast Bacilli, ZN Stain, Ziehl-Neelsen Stain, Sputum Smear for TB, Sputum Microscopy
What is the Sputum AFB Test?
The Sputum AFB test is a microscope examination of the phlegm you cough up from deep in your chest. AFB stands for acid-fast bacilli, a group of rod-shaped bacteria that hold on to a special stain even when washed with acid. Mycobacterium tuberculosis, the cause of TB, belongs to this group. A smear of your sputum is stained, commonly by the Ziehl-Neelsen method, and any red bacilli are counted against a blue background.
A strongly positive smear usually means the lungs hold a large number of bacteria, so the person is more likely to spread TB. The test has limits, though. Thousands of bacteria per millilitre are needed before they can be seen, so early cases and people with low immunity may have a negative smear. It also cannot separate TB from related mycobacteria or show drug resistance. TB PCR is more sensitive and specific, which is why doctors often add it when a smear is negative but TB is still suspected. Smears remain useful for watching the bacterial load fall during treatment.
What it measures: The presence and approximate number of acid-fast bacilli in a stained smear of sputum.
Parameters included (2)
- Acid Fast Bacilli: Seen or Not Seen
- Smear Grade: Scanty, 1+, 2+ or 3+
Why is this test done?
- Cough lasting 2 weeks or more, especially with fever or weight loss
- A chest X-ray that raises the suspicion of TB
- Judging how infectious a person with lung TB may be
- Following the response to TB treatment, when your doctor asks for a repeat smear
- Symptoms in a family member or close contact of a person with TB
When should you get tested?
- Persistent cough with phlegm
- Streaks of blood in the phlegm
- Fever that tends to rise in the evening
- Sweating at night with loss of weight
- Tiredness that keeps getting worse
How to prepare for the Sputum AFB Test
- 1Two samples are commonly advised, one on the spot and one early the next morning, so follow what your doctor or the lab asks.
- 2Rinse with plain water beforehand, and skip toothpaste and mouthwash.
- 3Cough deeply into the wide-mouthed container. About 2 to 5 mL of thick sputum is enough, while spit or nasal mucus is not suitable.
- 4Seal the lid, keep the container upright and hand it over soon after collection.
Sputum AFB Test normal range
| Parameter | Typical reference range |
|---|---|
| Expected result | No AFB seen in 100 oil immersion fields |
| Scanty | 1 to 9 AFB in 100 fields, usually with the exact count written |
| 1+ | 10 to 99 AFB in 100 fields |
| 2+ | 1 to 10 AFB per field, in at least 50 fields |
| 3+ | More than 10 AFB per field, in at least 20 fields |
This is the grading used for Ziehl-Neelsen smears in India. Fluorescence smears are counted differently, and your report’s wording takes precedence. Ranges are typical adult values and vary between labs, age and sex. Always use the range printed on your report and discuss results with your doctor.
Understanding your results
- AFB seen with typical symptoms strongly suggests TB, but related mycobacteria can look identical, so your doctor may confirm with TB PCR or a culture.
- A higher grade means more bacteria and usually a more infectious person. It does not mean the TB cannot be cured.
- AFB not seen does not rule out TB. If symptoms continue, ask your doctor about TB PCR and a chest X-ray.
- During treatment, a smear turning negative is a good sign. Keep taking the full course even once you feel better.
Sputum AFB Test – FAQs
What is the price of the Sputum AFB Test?
The Sputum AFB Test costs ₹450 at Live Line Health Care, at all 45 centres and for home sample collection.
What does AFB mean in a sputum test?
AFB means acid-fast bacilli, the type of bacteria that TB belongs to. They keep a red stain after an acid wash, which makes them visible under the microscope. “AFB seen” suggests TB, while “AFB not seen” means none were found on that smear.
What do scanty, 1+, 2+ and 3+ mean on an AFB report?
These grades show roughly how many bacteria were seen. Scanty is the lowest and 3+ the highest. More bacteria usually means a person is more infectious. Even scanty counts as AFB seen and needs prompt review by a doctor.
Why are two sputum samples needed for AFB?
Bacteria do not appear evenly in every cough, so a single sample can miss them. An early morning sample usually holds the most bacteria, as phlegm collects overnight. A second sample improves the chance of finding them.
Does a negative sputum AFB mean I do not have TB?
Not necessarily. Smears can only find TB when many bacteria are present, so a negative result is possible in early disease, in low immunity, or with a poor sample. If your cough continues, see your doctor about further tests.
Why was I asked for TB PCR after a negative AFB smear?
PCR can pick up much smaller amounts of TB than a smear. If your symptoms or X-ray still point to TB, your doctor uses it to look more closely. It also helps when a smear shows AFB but the exact germ is uncertain.
Can AFB be seen in illnesses other than TB?
Yes. Non-tuberculous mycobacteria, which live in soil and water, look the same under the microscope and can sometimes affect the lungs. They need different treatment, so a confirmatory test such as PCR or culture may be requested before treatment is decided.
Where can I get the Sputum AFB Test done?
At any of our 45 Live Line Health Care centres in 40 cities across Andhra Pradesh and Telangana, including Hyderabad, Visakhapatnam, Warangal, Kakinada and Nellore, or book home sample collection.
Medical disclaimer: This information is for general awareness only and is not a substitute for professional medical advice. Please consult a qualified doctor to interpret your results and before starting or changing any treatment.