Quest Diagnostics Stock Tumbles Amid Apple Partnership Buzz

Quest Diagnostics stock closed at $235.50 on September 8, 2026, down 0.69 percent from its previous close of $237.14 on the NYSE. This decrease comes as the Dow Jones Industrial Average fell 1.2 percent to 52,786.07, indicating a weak broader market backdrop for Quest Diagnostics shares.

The recent partnership between Quest Diagnostics and Apple's Health app is likely to be in focus today. Under this agreement, users in the US can schedule and purchase lab panels featuring over 50 key biomarkers directly through the Health app at approximately 2,000 Quest Diagnostics locations for $119.

This development could influence investor sentiment heading into today's session, as it integrates Quest's lab services into Apple's digital health offering. Quest Diagnostics itself highlighted the partnership in a newsroom communication on September 9, 2026, emphasizing that Apple Health app users will be able to order labs from Quest Diagnostics.