Sputum Culture- What does AFB Smear Positive mean?

Hi, when we get our test results for MAC/NTM it comes in 2 parts. First is the AFB (acid fast bacillus) "fast" test of the sputum. Positive means mycobacterium detected during a short incubation.
Then the specimen is sent for a longer term growing out of the bacteria in a culture medium. This can take up to two months, and is usually only done if the AFB is positive, or if you have a history of NTM infections. The long culture allows the doctor to see exactly which HTM you have, and may be followed by sensitivity testing, to see which drug(s) may kill you specific infection.
It is not unusual to have different results from consecutive cultures, I think maybe @rits @poodledoc and @thumperguy have had this experience in the past.

Thank you Sue! I am thinking it means that you have a higher bacterial load. I am headed to NJ this week so I will confirm.

Hi Sue. You did a beautiful job in spelling out in "layman" terms about the process in sputum testing. I've been dealing with MAC for almost 3 years now. I'm currently on oral Levofloxacin to try and treat Pseudomonas yet again. This has been the 5th time in three years. If this does not work I'll probably have to again do the 28 days of Tobramycin. I am on my third pulmonary doctor. First one immediately put me on the Big 3 for positive MAC. After 6 weeks I was taken off because I was not able to tolerate them. The doctor said he was probable not able to help me. Instead of doing a referral he just "quit" me. Through this forum another MAC sufferer told me of a doctor she found. He was 3 hours away but I got an appt. What a God send this man was. He guided me through my off and on infections and last summer I asked if he had someone closer to me to continue to manage my situation. He did recommend someone within 1 1/2 hrs away. I had been doing well up until the most recent positive pseudonymous report. One question I do have and I did present it to my current pulmonary doc... When sputum was tested at Emory the Pseudomonas was classified 1+ thru 4+. 4+ was the worse. So I asked my current doc how my sputum was classified at U. at B'ham he just said something like, "we don't rate that way." Any idea on what he means? Also he did say when he treats Pseudomonas using Tobramycin he usually does two weeks on and two weeks off. Is that schedule what you've experienced. I thought I'd seen on this forum that they would do one month on and one month off. It seems I've read that you have a lot of experience with the alternating treatments. Love your insight. So helpful. Faye

Where I go for my BE/NTM care, a smear and culture are done at the hospital lab concurrently. If bacteria grows on the plate (smear-positive) and can be seen under a microscope, it indicates a high load. The sample that is added to a broth is grown for up to 8 weeks as most mycobacteria are slow-growing.

So I asked my current doc how my sputum was classified at U. at B'ham he just said something like, "we don't rate that way." Any idea on what he means? My pulmonologist told me there is a two part answer to that - what each lab is capable of doing, and what the doctor orders. NJH and some others are able to do the scaled evals. His lab might not be?

As for inhaled Tobi, mine was "accidentally" two weeks on, two weeks off because I couldn't tolerate longer - lost voice & sore throat. Maybe he has found it works better this way?
Sue

@sueinmn Yes on different culture results. I have had 8 sputum cultures over the last 2.5 years. 4 Positive and 4 Negative. My first one came back Mycobacterium intracellulare (although looking at my medical portal there was considerable confusion at the lab before they finally came up with that). My second one came back Myocobacterium abscessus (after once again confusion at the local lab in TN, they sent the sample to some lab in CA to get the final result. My next 4 samples were sent to NJH (National Jewish Health in Denver) by my request. The first 2 were Negative the next one Positive for M. abscessus (but "few" colonies, only sensitive to Amikacin), the 4th one Negative. Then I switched my pulmonary care to Mayo clinic in Jacksonville, FL. I had 1 Negative culture followed by the last which was again Positive for M abscessus but only 2 colonies. Because of the low colony count my doctor was not concerned as all my other parameters were not changed and was told to continue my daily airway clearance and come back in 1 year. So the moral of my story is that you really can't trust labs with little NTM experience, insist on getting results from places such as NJH or Mayo or similar. Bill

Thanks Sue. Next time I communicate to clarify. I'm better since being on the Levofloxacin--will complete that on Tuesday. I'll try and submit another sputum them. My annual CT is also being done Tuesday. I should get a pretty good picture of how I'm doing. Happy Easter.

What does the 1+ 2+ 3+ mean?
What’ is considered cured?

Can you can the culture done without doctor's orders? Like can I go to LabCorp and compare with the one I do in the clinic since you mentioned labs were inaccurate and have different results.

The numbers represent the relative density of the bacteria they are testing for. Which Mycobacteria it is and whether it requires treatment is determined by culturing the specimen for 4-6 weeks.
Cured means 3 successive cultures grow no MAC.