Wiki Encounter for Protime level

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Code: Z51.81

Code Name: ICD-10 Code for Encounter for therapeutic drug level monitoring

Block: Encounters for other specific health care (Z40-Z53)

Excludes 2: follow-up examination for medical surveillance after treatment (Z08-Z09)

Details: Encounter for therapeutic drug level monitoring

Code also any long-term (current) drug therapy (Z79.-)

Excludes 1: encounter for blood-drug test for administrative or medicolegal reasons (Z02.83)


Excludes1: holiday relief care (Z75.5)


Code also: condition requiring care

Excludes1: follow-up examination after treatment (Z08-Z09)

Guidelines: Factors influencing health status and contact with health services (Z00-Z99)

Note: Z codes represent reasons for encounters. A corresponding procedure code must accompany a Z code if a procedure is performed. Categories Z00-Z99 are provided for occasions when circumstances other than a disease, injury or external cause classifiable to categories A00-Y99 are recorded as 'diagnoses' or 'problems'. This can arise in two main ways:
(a) When a person who may or may not be sick encounters the health services for some specific purpose, such as to receive limited care or service for a current condition, to donate an organ or tissue, to receive prophylactic vaccination (immunization), or to discuss a problem which is in itself not a disease or injury.
(b) When some circumstance or problem is present which influences the person's health status but is not in itself a current illness or injury."

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Best answers
Patient was in ER day before for a contusion of the head. She is on Coumadin and her PT & INR were elevated so she returns for a recheck of the PT & INR. What would be the code for this?



Best answers
Consider Z51.81, encounter for therapeutic drug level monitoring, as the primary diagnosis plus additional code Z79.01, long-term (current) use of anticoagulants. If the reason for anticoagulation is given/known, you may use that as the primary diagnosis instead of Z51.81 but still use additional code Z79.01. If the contusion is addressed/treated, you may also code that, but your post indicates the reason for the visit is to check the PT/INR.

The above is the information I have gotten from searching this topic on this forum, so you might also try a search for further information or to see how others handle it. I found slightly different ways, but the above is how I will code encounters for PT/INR monitoring.