What Is a Difficulty in Relying on Referent Values or Cutoffs

What is a difficulty in relying on referent values or cutoffs in converting a numerical test results into a yes-or-no clinical diagnosis?

A) Test results can fall beyond the cutoff values, leaving the diagnostic question unanswered.
B) The cutoff value is patient-specific and must be calculated for each individual patient.
C) The value considered to be the cutoff is variable depending on the prescribing physician.
D) There is a range of test result values that are shared between those with and without the condition.