Joan Rivers -- Yorkville Clinic No Longer Up to Snuff for the Federal Government

Joan Rivers' throat clinic just got a huge slap on the wrist after a federal investigation -- and now a ton of patients will have to get treatment somewhere else.

As we've previously reported ... the Dept. of Health and Human Services found a ton of flaws at Yorkville Endoscopy Center after Joan's death -- and gave the clinic a list of things to improve ... or else.

Well, according to a new DHHS report ... Yorkville still doesn't pass muster in a bunch of areas -- most interestingly ... failing to properly complete and document post-anesthesia evaluations of patients.

TMZ broke the story ... the clinic director Lawrence Cohen is on record saying it's not cost-effective to pay an anesthesiologist for procedures like the one Joan was getting when she died.

As a result, feds are cutting off Medicare reimbursement to Yorkville -- meaning, if you're a Medicare or Medicaid patient ... your benefits will no longer be accepted there as of January 31.