# Question regarding Z51.81



## trinabell! (Nov 22, 2015)

Is it required to ALWAYS list a Z79.-- code when using Z51.81?  I am getting conflicting information and would like to pass on to one of our physicians that uses this code.


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## CodingKing (Nov 22, 2015)

Yes, the ICD-10 book says "code also". A patient wouldn't need therapeutic drug monitoring if they weren't on a drug that needed to be monitored. Z79.- lists the type of drug being monitored.


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