. . . allowing the user to control and build up an overview of their personal wellness,
. . . using whatever combination of health and fitness iOS apps and devices they choose.
But such was the serious nature of the last minute HealthKit bug,
. . . that Apple locked the tool down entirely, so it’s effectively not in the current version of iOS 8. Cupertino also pulled apps with HealthKit integration off the App Store.
09-20-2014 Source: Apple Cauterizing HealthKit At Launch