Is Z20 a billable ICD-10-CM code?

No. Z20 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does Z20 sit in the tabular list?

Factors influencing health status and contact with health services (Z00-Z99), in the block Persons with potential health hazards related to communicable diseases (Z20-Z29).

What cannot be coded together with Z20?

Z20 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

Z20

Z20 — Contact with and (suspected) exposure to communicable diseases

Non-billable headerICD-10-CM

Z20 is a non-billable header ICD-10-CM code for contact with and (suspected) exposure to communicable diseases. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

carrier of infectious disease (Z22.-)
diagnosed current infectious or parasitic disease -see Alphabetic Index

Excludes2 — not included here, but may coexist

The excluded condition is not part of this code, but a patient can have both. You may code both.

personal history of infectious and parasitic diseases (Z86.1-)

Other codes that can never be billed with Z20

These codes carry an Excludes1 note pointing at Z20. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading Z20 alone.

B20Human immunodeficiency virus [HIV] disease
Z21Asymptomatic human immunodeficiency virus [HIV] infection status

Risk adjustment

Z20 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead Z20

10 child codes. Green means billable.

Questions about Z20

Is Z20 a billable ICD-10-CM code?: No. Z20 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does Z20 sit in the tabular list?: Factors influencing health status and contact with health services (Z00-Z99), in the block Persons with potential health hazards related to communicable diseases (Z20-Z29).
What cannot be coded together with Z20?: Z20 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.