Someone takes a medical exam for some reason ''other'' than genuinely wondering about his/her health. Surprisingly, the test is positive. (Meaning they have whatever condition they were tested for.) Depending on the show and the condition, this can be PlayedForLaughs or PlayedForDrama. In the latter case, it may be a LethalDiagnosis.
[[AC: Anime and Manga]]
* At the end of the final episode of the first season of ''Manga/ICantUnderstandWhatMyHusbandIsSaying'', [[spoiler: Kaoru ends up taking a pregnancy test. Initially it appears negative, but when she shows it to Hajime it suddenly turns positive.]]

[[AC: Fanfiction]]
* Chapter 10 of the ''{{Superjail}}'' fanfic ''Fanfic/AllInTheFamily'' has Cherice, who thinks she may be pregnant. The Mistress decides to come along with her to the doctor for some tests, because no one else will. Guess who turns out to be pregnant.

[[AC: Comics]]

* The Swiss French-language graphic novel ''Jo'' is about AIDS. The ([[TomboyishName teenage girl]]) title character meets a boy, Laurent, who is tormented by the memories of his beloved brother who died of AIDS and he is himself afraid of having the disease. She decides that they will be tested together to reasure him. [[spoiler:To their greatest shock, Jo herself is diagnosed with AIDS and the rest of the book is about her dealing with the disease until she dies.]]

[[AC: Film]]
* In ''Film/BabyMama'' [[spoiler: Angie's pregnancy ruse gets her into the obstetrician's office, and she discovers that she actually is pregnant]].
* Played for tragedy in ''Film/{{Kids}}''. A character who has only had sex once has an HIV test to encourage her promiscuous friend to do the same. Guess which one's positive.

[[AC:Live Action Televsion]]
* ''Series/ILoveLucy'': Lucy forces Ricky to go to the eye doctor where they find out that his eyes are perfectly's Lucy who can't see the eye chart correctly! In typical Lucy fashion, wackiness ensues.
* ''TheBradyBunch'': Carol lets the doctor check her tonsils to show Cindy that it won't hurt. Turns out Carol and Cindy ''both'' need their tonsils out.
* Repeated on ''Series/TheNanny.'' The daughter Gracie only had the flu, but Fran had to have her tonsils out.
** Repeated later when oldest daughter Maggie thinks she's pregnant and goes to a gynecologist for a test. It turns out negative, but when the doctor lists some of the signs Fran interrupts to say ''she's'' been feeling nauseous and tired... [[spoiler: Subverted two episodes later, when it turns out she wasn't really pregnant.]]
* ''Series/TheGoldenGirls'': Dorothy takes a hearing test to show Sophia it's no big deal. Sophia does ''not'' need a hearing aid; Dorothy does.
* ''Series/GrowingPains'': Maggie is doing a series of news reports about regular medical checkups, and thus undergoes all the usual tests. This is how she discovers she's pregnant.
** In another episode, Jason allows a pediatrician to examine him to show a teenage boy it's no big deal. This is how his hernia is discovered.
* In {{Scrubs}}, there was an episode with a hypochondriac patient who demanded every test available. Eventually, as they were running out of tests and trying to convince the guy he was obviously perfectly healthy, Dr. Cox sets him up with an extremely uncomfortable test for a one-in-a-million condition in the hopes that he'll go away. It unexpectedly turned out positive.
* In ''{{Coupling}}'', Sally buys three pregnancy tests because she doesn't know what a negative test looks like and asks Susan and Jane to take one each. Of the three of them, it's the apparently infertile Susan who turns out to be pregnant.
* In ''ThatsSoRaven'', Raven and Corey go to the dentist. Corey's scared, so (after having a vision in which one of the pair is shown to need a filling) Raven gets in the chair to show him that it's not so bad. Guess who needs the filling?
** The exact same scenario was done years earlier on ''TheJackBennyProgram''. Jack goes with a neighborhood boy to the dentist because the boy is scared. Guess which one needs a tooth pulled?
* An episode of {{ER}} had Carter demonstrating to several medical students how to examine a patient's lymph nodes--only to discover a lump in the neck of the student he was examining. After doing a biopsy, he gently informed him that he had lymphoma.
* During an episode of ''DoogieHowserMD'', the senior Dr. Howser flashed back to a time when he was examining his son, who had asked him to demonstrate to him. Upon examining his abdomen, the boy yelped in pain, and the horrified Dr. Howser realized he'd just discovered that his son had leukemia.
* On ''OneLifeToLive'', Blair was suffering from dizzy spells, but terrified of going to the doctor and finding out what might be wrong. On-again, off-again paramour Max offered to go with her. Sure enough, Blair only had an allergy, while Max was found to have an aneurysm.
* On ''{{Frasier}}'', Niles gets a toothache, and in order to avoid going to the dentist and having a cavity drilled, he decides to get a full physical, on the off chance that the pain could indicate a more serious condition. Everyone else spends the entire episode pointing out that's a complete overreaction to a simple problem. In the end, Niles finally comes around and admits he was being irrational, just before he's informed that he has a serious heart condition.
* Subverted on ''Series/{{Continuum}}''. In "So Do Our Minutes Hasten", Alec shows off his new health-monitoring wrist bracelet, the Halo, to the Piron board. He convinces a naysayer of its value by having him try it out, and identifying markers for colon cancer. In private, however, he admits that the "data" it collected was all guesswork and information from the man's company insurance files, and he doesn't have a working prototype yet.
* On an episode of DifferentStrokes, Mr. Drummond purchased a device that measured stress on his doctor's advice. Sure enough, his rating was high, but when the kids goofed around with it, Willis' were off the chart (he was coping with schoolwork, extracurricular activities, running for class office).
* In the ''Series/HowToGetAwayWithMurder'' episode "It's All My Fault", Connor and Oliver are getting back together after a bad breakup. Oliver wants Connor to get an HIV test before they have sex again and decides that it would be romantic to get tested together. Connor works himself into a panic over all of the risks he's taken. Connor tests negative. Oliver tests positive.
* In season 1 episode 11 of ''Series/QueerAsFolkUS'', after Ted discovers that one of the guys he's been with is now HIV positive, Emmett gets tested along with Ted out of solidarity. The clinic gets back to Ted with the good news right away but tells Emmett to come in again on Monday, making Emmett sure he must be positive. [[spoiler: It's a {{Subversion}}. Emmett's negative. There's just a problem with his method of payment.]]
* In ''SeventhHeaven'', Mary must undergo a physical before she leaves for basketball camp that summer. The doctor ropes Annie into having one too, and this is how she finds out she's pregnant with the twins. (But not before an episode-long assumption that ''Mary'' is the pregnant one due to the doctor mixing up their results.)

[[AC: Western Animation]]
* In ''WesternAnimation/TheSimpsons'', when Marge and Homer are mistakenly assessed as negligent parents, they are forced to attend a parenting class which Marge initially fails due to a false positive diagnosis for crack and PCP.

[[AC: Real Life]]
* John Holmes got an AIDS test to encourage other porn stars to do so. He tested positive.
* A reporter for the Australian 60 Minutes had this happen during a story on cancer.
* There have been instances of men finding an unused pregnancy test lying around and deciding to take it [[ItAmusedMe just for fun]], only to have it turn out positive (a positive pregnancy test from a man can be an indication of testicular cancer).
* Debbie Allen based an episode of ''Series/ADifferentWorld'' off an experience she had when she was college--when a friend of her feared she was pregnant, she accompanied her to the doctor and took the test as well. However, the positive Debbie received was ''very'' unexpected, as she hadn't even ''had'' sex as yet. (the results were mishandled)