New Year's Eve, where auld acquaintance be forgot. Unless, of course, those tests come back positive.

Jay Leno riffs on the traditional New Year’s Eve sentiment from “Auld Lang Syne” (“should auld acquaintance be forgot”), which evokes nostalgia and the ritual of letting the past recede as a new year begins. The punchline abruptly twists that ideal into a modern, anxious reality: medical testing and the possibility of a “positive” result. The humor comes from collision—sentimental communal celebration versus private health fears—suggesting that some “acquaintances” (past encounters, exposures, or consequences) can’t simply be forgotten if they return as test results. It’s a classic late-night style joke that uses a familiar cultural reference to set up an unexpected, contemporary reversal.