2Day CPET Test Results

[LiveAgain]

When I heard that the 2 day test may be the best biomarker for CFS I wanted this test. I know I have a CFS diagnosis, but do I really have CFS? I traveled to Ithaca last month and did the testing with Betsy Keller (who by the way is lovely and was very patient with all my questions.). My results came in and I did not show the second day response on the two measures that are so widely talked about - VO2 Max and AT. Everything was low (really low), but I didn't do any worse day 1 to day 2. (And I will be following up with a cardiologist about those low results.)

The one area I showed a difference falls under "hemodynamics" - day 2 my blood pressure failed to increase appropriately during the latter part of the test. What complicates matters is that I have POTS (likely due to autonomic neuropathy) so my lack of BP response may have been a result of this, however, according to Ithaca the fact that it only happened day 2 may mean it was triggered by PEM and therefore, CFS can't be ruled out. Or was it just what my wacky POTS was doing that day and nothing to do with PEM?

I wanted to show the second day response because I wanted to fit into a typical CFS pattern and have some more confirmation that this is likely my disease. I've always feared, what if one day there is a good biomarker for CFS and I test negative for it? I've been ill over 16 years with no good explanation, I've been tested for everything under the sun to no avail, I need for this to be it. I was in contact with another person with CFS who had the same outcome on testing... poor results, but consistent both days.

Have enough of us had the 2 day testing done to be sure this is our potential biomarker? Are we pretty sure we should be pushing the government on this 2 day issue? What if the second day response became a diagnostic requirement and you did fine on the test? Either I don't have CFS or this isn't a definitive biomarker. Any thoughts are welcome.

 

[Sea]

I understand your fear LiveAgain. I approach every test with mixed feelings both wanting validation that this is the illness I have and yet hoping to turn up something treatable instead. I think as long as particular bio-markers are used to divide people into subsets rather than into sick/not sick it could be a good thing.

 

[GracieJ]

I share your concern.

However, after 23 years of mostly being in the dark except for one doctor who opened the door to accurate symptoms assessment, I no longer worry about it too much. I do have the thought of getting an extensive panel of conclusive tests that show all the abnormalities, show the cytokine "storm," the spinal fluid anomalies, NMH and OI on paper, exercise test, mitochondrial dysfunction, etc. It would be poetic justice to KNOW after all these years - See? Told you so. I am not crazy. I have a full-spectrum neuro-immune disorder that is probably a close cousin to MS or Lupus - or maybe more like post-polio syndrome, or non-HIV AIDS. I'd welcome the label. The ICC describes my life.

I am getting better as the weeks and months pass. So if my symptoms are dwindling, does it mean I still "have" this? Does it mean I am entering some form of remission? What would the ultimate post-syndrome lab picture look like? What would have dropped back to normal ranges? What would still show up after the fact? How long will it be before physicians can recognize the lab profile post-syndrome, let alone active?

Or am I to hear the unending - and more and more humorous to me - refrain, Well, if you are getting better, then you never had this. Crazy-making!!! So.... I just am not worried about labs anymore. I have been sick for a loooooong looooooong time, been there, done that, DO NOT want the T-shirt , thank you very much!

 

[Hope123]

Two possible reasons I can think of:

1) No medical test is 100% sensitive, not even the HIV screening tests......although they're something along the lines of 99.9...%. Sensitivity means how many patients with the true disease the test picks up. So a sensitivity of 90% means that 90% of all patients with a disease will have an abnormal test result but 10% will have what looks like a normal test results EVEN THOUGH they have the disease.

Right now, we don't have data on what the sensitivity for 2-day CPET is for ME/ CFS patients. So you could truly have CFS and not have an abnormal 2-day CPET. In terms of your fears about definitions, non-ME/CFS definitions often specify, when a test is not highly sensitive, that conditon XY may be present even with a normal result on test ABC. It's all about what is found eventually.

2) Alluding to subgroups, work by Julia Newton and the Lights in Utah suggest that there may be a group of people with POTS/OI/NMH that have primarily POTS/OI/NMH and not ME/CFS. Some of the symptoms of CFS and POTS/OI/NMH overlap so it's difficult to separate the two clinically and there are people with "true" ME/CFS who may also happen to have POTS.

How to tell the difference? The Lights show the POTS/OI/NMH group have different gene expression compared to the ME/CFS group. Also, therapeutically, some folks with a diagnosis of ME/CFS get substantially or wholly better with POTS/OI/NMH treatment, arguing they don't have 'true" ME/CFS. On the other hand, the treatments for POTS/OI/NMH don't work for everyone with these conditions so you can still have someone with "only" these conditions who doesn't get better despite treatment.

[Yeah, it's complicated.]

3) Not a reason but a question. When you did Betsy Keller's test, what did they use as the stopping point for you? Did they ask you how much exercise you could tolerate? Or was it stopped when your blood pressure did not go up as expected? (For CPET done for heart disease, failure of blood pressure to rise is one sign of possible heart problems.) Or was it stopped when you reached certain measures like the respiratory exchange ratio? At PFL, they use the RER because it's an objective measure.

 

[LiveAgain]

Interesting, Hope, about the different gene expression POTS vs. ME/CFS. I hadn't heard about that. I've also wondered, since there is overlap, are they capturing some dysautonomia patients and putting us into ME/CFS where we don't belong. Sounds like maybe?

The test was stopped when I couldn't do anymore. She has you point to a chart with numbers that reflect your perceived exertion level and when you get pretty close to or at 'I can't do this anymore' the test stops. On test day 2, my stop point coincided with when my BP started dropping. She may have stopped the test for me if I had tried to keep on going, not sure. Even though I only lasted around 7 minutes I met all three criteria for maximum effort; RER, Maximum Heartrate and Rating of perceived exertion so the results are valid.

 

[Little Bluestem]

What if the second day response became a diagnostic requirement and you did fine on the test?

You didn’t do fine on the test, you did equally poorly both days. Do you know how your first day compares to other ME patients’ first day? Maybe if you do badly enough on the first day, you don’t get any worse on the second.

I do think we need more experience with this test and particularly with those who are as severely ill as can safely take the test.

 

[LiveAgain]

Right Bluestem, what I meant by doing "fine" is you reproduce your results. I thought the whole point of doing the test 2 days in a row is to prove post exertional malaise which is one of the hallmark symptoms of ME/CFS. Seems there are many illnesses that can cause you to perform poorly in general, but my understanding of the research is that a second day change is unique to ME/CFS. I hope they do more large studies on this.

 

[Little Bluestem]

Maybe the PEM occurs the second day in less severe ME. Maybe in severe ME the PEM sets in before the first day test is over. We won't know until more people with different levels of illness take the test.