undertriage

under- +‎ triage

undertriage (plural undertriages)

1. The diagnosis of an injury as being less traumatic than it actually is
   • 2015 August 1, “Trauma with Injury Severity Score of 75: Are These Unsurvivable Injuries?”, in PLOS ONE‎, DOI:10.1371/journal.pone.0134821:

     However, our prior study on undertriage of major trauma patients indicated that a significant proportion of trauma patients with an ISS = 75 survived.

undertriage (third-person singular simple present undertriages, present participle undertriaging, simple past and past participle undertriaged)

1. To make such a diagnosis

• overtriage