Quick Question. How Can The Rv On Pft Be Low

Posted on Thu, 11 Apr 2019

Question: Quick question. How can the rv on pft be low at 68% of predicted but the FVC on spirometry and TLC from body box both normal? I had sarcoidosis 5 years ago and CT scan in 2016 show that it is gone. My doctor cleared me and said only to come back if I get sick.

Answered by Dr. Drkaushal85 (1 hour later)

Brief Answer:
There might be some technical error or leakage.

Detailed Answer:
Thanks for your question on Ask a doctor forum.
I can understand your concern.
Ya, this is strange.
There might be some technical error or leakage issue, otherwise this is not possible.
Please let me know
1. Do you have any symptoms?
2. How old is this report?
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. Prasad

Follow up: Dr. Drkaushal85 (28 minutes later)

Here is the actually copy of the reports. The only thing that may be a concern was the DLCO which was at the LLN. Let me know if you can see the two reports?

Follow up: Dr. Drkaushal85 (6 hours later)

the other thing that is odd is if you look at the predicted score of the TLC verses the actual score the difference is really all in the residual volume. that would mean the other 3 components of the TLC are all 100% of predicted basically. To me it seems a bit odd which I am assuming why my doctor didnt even mention it to me.

Answered by Dr. Drkaushal85 (19 hours later)

Brief Answer:
No need to worry for this low RV.

Detailed Answer:
Thanks for your follow up question on Ask a doctor forum.
I can understand your concern.
First of all, sorry for late reply as I was busy.
Yes, I have gone through the attachment you have attached.
No need to worry for low RV as your all other values are stable and normal.
I will be happy to help you further. Wish you good health. Thanks.

Above answer was peer-reviewed by : Dr. Raju A.T

Follow up: Dr. Drkaushal85 (5 hours later)

thanks, I feel okay so not really worried about the results just more of a curiosity. Is the RV reduced because of some type of calculation error? I know the TLC is VC RV. Backing into the numbers I know my VC is 4.56 which oddly is higher than my FVC spirometry number. Shouldn't the FVC actually be higher than the VC?

Answered by Dr. Drkaushal85 (3 minutes later)

Brief Answer:
Yes, you are right.

Detailed Answer:
Thanks for your follow up question on Ask a doctor forum.
I can understand your concern.
Yes, you are right.
That's why I told earlier that it is mostly due to technical error.
Don't go into much details. Enjoy your life.
I will be happy to help you further. Wish you good health. Thanks.

Above answer was peer-reviewed by : Dr. Raju A.T