HealthCareMagic is now Ask A Doctor - 24x7 | https://www.askadoctor24x7.com

What Causes False Positive In A Pulmonary Function Test?

Posted on Fri, 15 Jul 2016

Question: i WENT TO MY FAMILY DOCTOR AND I HAD NOTICED A SLIGHT COUGH EVERY ONCE IN AWHILE (NO WHERE NEAR BEING CHRONIC) i AM ABOUT 70 LBS OVER WEIGHT AND WHEN i WALK I GET ALITTLE WINDED. hE SENT ME FOR A CHEST X-RAY AND A BREATHING TEST. tHE X-RAY HAD SOME SPOTS ON IT AND THE BREATHING TEST CAME BACK @ 20% AND THE PRINT OUT READ PROBABALE PAULMANARY FIBROSIS. i WENT TO A PAULMANARY SPECIALIST HE SAT DOWN WITH ME EXAMINED ME ASKED ALL KINDS OF QUESTIOS,AND SAID i DON'T SEE IT HE SAID HE'S 78% SURE THAT IT IS NOT pAULMANY FIBROSIS AND TO COME BACK IN A YEAR AND WILL DO THE BREATHING TEST AGAIN. iS IT POSSIBLE THAT THE BREATHING TEST WASN'T ACCURATE ?

Answered by Dr. Drkaushal85 (41 minutes later)

Brief Answer:
Yes, breathing test can be false positive.

Detailed Answer:
Thanks for your question on Healthcare Magic.
I can understand your concern.
You had PFT (pulmonary function test).
And this test can falsely indicate disease.
Actually PFT is effort dependent test.
Patient has too make full effort in the machine to get accurate test results.
So you might have not given 100% in the test. So results are less as compare to standard values.
So PFT report can be inaccurate if proper effort is not put by patients.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.

Above answer was peer-reviewed by : Dr. Yogesh D

Follow up: Dr. Drkaushal85 (28 minutes later)

He said that i should losse about 50 lbs and retake the test in a year can weight play a part in my breathing on the test. I don't feel bad ,i cough once in a great while (i think that's a sinus drip cough) I work all day yes i'm 63 and i do take a nap when I get home from work . He said he thought the shadeded area in my chest x-ray was caused by belly fat(lower lobe) my family doctor thought he heard a crackling sound when he listened to my back while doing heaving breathing. But the specialist said he thought maybe he heard something very very faint but wasn't sure.What could that have been ?

Answered by Dr. Drkaushal85 (9 minutes later)

Brief Answer:
Can you upload the chest x ray?

Detailed Answer:
Thanks for your follow up question on Healthcare Magic.
I can understand your concern.
Yes, belly fat can give rise to such shadows on chest x ray.
And yes, weight loss might improve your values on PFT.
Please let me know
1. Have you put optimal effort while doing PFT?
2. Can you upload the chest x ray image? This will be of great help for me to guide further.
Please reply me answers of above asked questions, so that I can guide you better. I will be happy to help you further. Wish you good health. Thanks.

Above answer was peer-reviewed by : Dr. Yogesh D

Follow up: Dr. Drkaushal85 (39 minutes later)

I will try to up load the x-ray,but i will have to get it from my Dr first :)

Answered by Dr. Drkaushal85 (4 minutes later)

Brief Answer:
What about effort in PFT?

Detailed Answer:
Thanks for your follow up question on Healthcare Magic.
I can understand your concern.
OK, I will wait for the x ray image.
What about effort in PFT?
Did you give optimal effort during PFT?
Please reply me answers of above asked questions, so that I can guide you better. I will be happy to help you further. Wish you good health. Thanks.

Above answer was peer-reviewed by : Dr. Veerisetty Shyamkumar

Follow up: Dr. Drkaushal85 (29 minutes later)

I thought I gave a optional effort but some of the blowing and the way you had to hold your breath was some what confusing so I probably didn't give exactly 100%

Answered by Dr. Drkaushal85 (1 hour later)

Brief Answer:
Do you smoke?

Detailed Answer:
Thanks for your follow up question on Healthcare Magic.
I can understand your concern.
PFT menuere is very difficult when patient is performing for the first time.
If you can give me PFT graph image, I can tell you about your effort.
But I think you are also not having this.
I forget to ask one important factor.
Do you smoke?
Please reply me answers of above asked questions, so that I can guide you better. I will be happy to help you further. Wish you good health. Thanks.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Drkaushal85 (17 hours later)

good morning no i have never smoked

Answered by Dr. Drkaushal85 (7 minutes later)

Brief Answer:
Possibility of pulmonary fibrosis is very less in your case.

Detailed Answer:
Thanks for your follow up question on Healthcare Magic.
It is good afternoon in my part of world.
I can understand your concern.
It is good that you are non smoker.
By your overall history and our discussion, I don't think you are having pulmonary fibrosis.
You should follow pulmonologist's advice.
Get done repeat PFT after 1 year.
During this time, try to loose weight.
Hope I have solved your query.
If you are not having further queries, then please close the conversation and rate my answer.
You can ask me directly on bit.ly/askdrkaushalbhavsar.
Wish you good health. Thanks.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar