“B Positive” — well, that’s easy for CBS to say. The high anxiety of the presidential election this week makes the prospect of watching the network’s new sitcom, where characters seem to know nothing of global pandemics and collapsing democracies, seem like a waste of time. It’s hard to call anything a waste of time these days, amid so much wasted time.

And “B Positive,” created by Marco Pennette and premiering Thursday night on CBS under producer Chuck Lorre’s banner of mainstream hits, has the distinction (both positive and negative) of being the first new prime-time comedy to premiere in this strange and postponed fall season. With a cheerful dose of dutifulness, the show all but insists that life must go on for all of us. Even the mundane must endure.

Interestingly (sort of), a life-or-death medical matter is at the crux of “B Positive’s” premise: Thomas Middleditch (“Silicon Valley”) plays Drew, a recently divorced Connecticut therapist who learns that his urinary issues have confirmed the worst: imminent renal failure. Dialysis looms, and Drew’s doctor urges him to ask people he knows if they might be willing and able to donate one of their kidneys to him. Start with family, the doctor suggests.

“Oh, good, a Republican kidney,” Drew says.

“[The kidney] will just tell you to pee, it won’t tell you which bathroom to pee in,” the doc replies.

At a friend’s wedding, Drew meets an old acquaintance from high school, Gina (Annaleigh Ashford from “Masters of Sex” and “Bad Education”), a big-hearted but rambunctious party girl who works as a shuttle driver for an assisted-living facility (where, lo and behold, Linda Lavin is slumming it in the role of one of the residents). Gina offers to be Drew’s kidney donor — and a test confirms that she’s a good match, on the condition that she can stop drinking and doing drugs for three months.

Gina agrees to try, while Drew heads off to dialysis three times a week, where he meets a very sitcom-like trio of fellow patients — a former pro-football player (Terrence Terrell), a sharp-elbowed corporate striver (Briga Heelan) and an affable dentist (David Anthony Higgins) — who are all tended to by a gay, no-nonsense nurse (Darryl Stephens).

When you throw in Drew’s ex-wife (Sara Rue) and 12-year-old daughter, Maddie (Izzy G.), as well as Gina’s dimwitted best friend (Kether Donohue), “B Positive” suddenly has more characters than the latest season of “Fargo,” and barely a chance to focus on its overall story. As Gina moves into Drew’s house to work on her sobriety (and elude the loan shark who’s after her), it’s never clear what sort of outcome we should be hoping for here: true love or surgical success or a combination of both?

Some viewers may ask what they see as the bigger question: How did two actors as talented as Middleditch and Ashford wind up in a mainstream sitcom?

That’s actually quite easy to answer: Go ask Melissa McCarthy about “Mike & Molly” syndication royalties (or Allison Janney about “Mom,” or any of “The Big Bang Theory” nerds) and you will wonder no more why it’s still a choice gig, even in this sleek, streaming TV era of ours. And it’s not entirely accurate to say that Lorre’s shows sand away all traces of edginess; Lorre has perfected a tone that pushes just far enough into raunchy territory that somehow placates network brass while not completely patronizing the viewers.

Here, gallows humor seems to do the trick, such as one scene in which Drew confidently tells his dialysis buddies that he has a donor already — someone he knows and likes. They reply that they’d be willing at this point to accept a kidney from humanity’s worst: Hannibal Lecter, one says. Ayatollah Khomeini, says another.

“Mother Teresa,” says the dentist.

“How was she a bad person?” someone asks.

The dentist replies that he did not see the pattern of the joke.

That muffled groan is either the ghost of the late writer Christopher Hitchens begging to differ on the subject of Mother Teresa’s saintliness, or it’s the sound of a critic ending on a note of indifference. Positive or negative, we’ll just leave it be.

B Positive (30 minutes) premieres Thursday at 8:30 p.m. on CBS.