Examples:
(1) hypothyroid patient with normal serum T4 level but a very high TSH concentration
(2) normal serum iron but absent iron stores in the bone marrow
(3) pain patient with prescribed opioid in urine but none in a hair sample
(4) transplant patient with normal immunosuppressant levels but signs of rejection
Reasons:
(1) The person wants to mask drug diversion.
(2) The patient does not want to be yelled at by the physician.
(3) The patient needs to hide the noncompliance.
Hazards of this practice for the patient:
(1) The underlying condition is not being treated.
(2) The patient may take too much of the drug while trying to get the serum levels higher.
(3) The patient may become symptomatic if the drug requires tolerance to develop.
Failure to consider this can result in a complex and expensive workup.
One way to detect this is to find that the patient has a lot more drug that s/he should if they were compliant. However, this probably only works once.
The diagnosis usually requires a targeted discussion with the patient about compliance and why adherence to a regimen is important.
