The failure to diagnose a condition in a significant proportion of a patients(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "underdiagnosis" in a sentence
"Well, there probably is some overdiagnosis, but the worse problem is the underdiagnosis."
"The CDC report looked at people already in the health-care system, "but there is a big problem with underdiagnosis and undertreatment," he said."
"The report, Delivering Male, shows how the underdiagnosis of depression in men, the high rate of male suicides and largely unrecognised problems like eating disorders can be more effectively tackled."