NEW: NYC Health Dept has sent alert to all medical providers advising *not* to use anti-body tests to diagnose prior covid infection nor to assess immunity.

This is due to high rate of false negatives/positives and uncertainty about how immunity works.

Dose of reality folks. pic.twitter.com/ZEHsbt3aNe

— Mark D. Levine (@MarkLevineNYC) April 23, 2020