Only members of the vast army of the long-term undiagnosed can know what it is to fight back tears of disappointment at the news that you don't have a horrible disease. Sure, Disease X would have meant you were going to die a horrible death, but not before years of being slowly disfigured by pustulant boils followed by an extended period of smearing feces on your naked body whenever the moon was full. But at least you would have had an answer to the question that sparks and flares violently across your every synapse: what is happening to me?

The cycle goes like this. The doctor, having exhausted her library of top ten diseases, starts mining your data from new angles, looking for connections in every database she can get her hands on. Disease X starts to look plausible. She floats it by some colleagues, including a specialist in this particular malady. Yes, they decide, this is probably it. The Disease X specialist is especially excited, as there are so few patients in your region. They'll just need a couple more tests to confirm.

So you offer your blood and, your urine, and you wait. The test for Disease X is only processed in Rochester or Sante Fe, and only on Thursdays when the moon is full. It will take a while. Eventually, against your better judgement, you open the laptop and look up the disaease. And what you read is truly horrifying. Your brain makes sounds you didn't know a brain can make, and briefly you think you are going to pass out. It can't be that—anything but that. Oh please, not Disease X. You close the laptop and vow never to look again.

If the call from the doctor came at that point, you would gasp with joy at the good news. You would run down to the nearest place of worship and light a candle in honor of Saint Jarvis, patron of those who do not have Disease X. But of course the call does not come. And with every day it does not come, you become increasingly convinced that this is going to be it. You feel it in your bones. You have Disease X, and you might as well come to terms with your fate.

And your fate—gruesome, puss-filled and feces-smeared though it might be—does have its upsides. First of all, there's the the online support group. Lurking in the virtual shadows, you read the grief, bonding and genuine caring of the patients in the grips of the disease, and you start to imagine yourself partaking of those comforts. Someone to talk to. Someone who understands what you are experiencing. There you find a network of families to which your spouse can turn once you have dissolved, as 94.7% of all those afflicted with Disease X inevitably do, into a frothy puddle of bone and puss.

Your wife, who is a fearless runner, can enter the annual half-marathon to raise money for future research. Maybe one of your brilliant, scientifically-inclined children will go on to cure the disease, or even just ameliorate its most gruesome symptoms. And even if they both end up (shudder) English professors, they will at least have a story about what happened. And you will have an answer at last to the perpetual question asked by every well-intentioned friend as they note your limp, your rash, the hair on your eyeballs or your increasingly erratic behavior when the moon is full. "What's wrong with me? Oh, I have Disease X," you will say, pointing bravely at the ribbon on your chest. It is a particularly fetching ribbon.

Your friends will now have something to research in turn, with wikipedia providing the gruesome details. They will perhaps start wearing the fetching ribbon in solidarity. Maybe they will join your wife on that half-marathon while you watch from the sidelines, cheering the runners on. There will be t-shirts. And energy drinks. But most of all there will be an answer to that question.

And so it is that when, weeks later, the results are finally conveyed, you find yourself fighting the urge to cry when your doctor tells you that you don't have Disease X. "Of course this means we're back at square one in terms of figuring out what is going on, but this is good news. I wouldn't wish Disease X on anyone," your doctor says. "I'll get back in touch about possible next steps in the diagnostic process, but for now let's take a 'wait-and-see' approach, ok?" And before you can think of an appropriate response, she is gone.

Yes, no one but the vast army of the terminally undiagnosed can understand the soul-crushing despair of learning that you will not, in fact, die of Disease X. No one, of course, except your wife, that fearless runner, who takes you in her arms when you tell her the news and whispers (quietly, so the kids can't hear), "I'm so sorry."