1. A wrong, incorrect, or mistaken identification of an illness: "Harm may result when a patient gets a misdiagnosis because he or she may get an incorrect therapeutic treatment."
2. A conclusion, identification, or decision reached by mistake: "Unless there is proper testing, the potential for a misdiagnosis can be considerable."

"After several misdiagnoses, the committee found out what the problem actually was and then tehy were able to come up with a successful solution."