Is O35 a billable ICD-10-CM code?

No. O35 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does O35 sit in the tabular list?

Pregnancy, childbirth and the puerperium (O00-O9A), in the block Maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48).

What cannot be coded together with O35?

O35 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

O35

O35 — Maternal care for known or suspected fetal abnormality and damage

Non-billable headerICD-10-CM

O35 is a non-billable header ICD-10-CM code for maternal care for known or suspected fetal abnormality and damage. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.

This code requires a 7th character

One of the following 7th characters is to be assigned to each code under category O35. 7th character 0 is for single gestations and multiple gestations where the fetus is unspecified. 7th characters 1 through 9 are for cases of multiple gestations to identify the fetus for which the code applies. The appropriate code from category O30, Multiple gestation, must also be assigned when assigning a code from category O35 that has a 7th character of 1 through 9.

0: not applicable or unspecified
1: fetus 1
2: fetus 2
3: fetus 3
4: fetus 4
5: fetus 5
9: other fetus

Excludes1 — never code together

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

encounter for suspected maternal and fetal conditions ruled out (Z03.7-)

Code also

Both codes may be needed to describe the encounter fully. Sequencing depends on the reason for the visit.

any associated maternal condition

Includes

Conditions this code covers.

the listed conditions in the fetus as a reason for hospitalization or other obstetric care to the mother, or for termination of pregnancy

Other codes that can never be billed with O35

These codes carry an Excludes1 note pointing at O35. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading O35 alone.

O09.829Supervision of pregnancy with history of in utero procedure during previous pregnancy, unspecified trimester
Z03.7Encounter for suspected maternal and fetal conditions ruled out

Risk adjustment

O35 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 O35

18 child codes. Green means billable.

Questions about O35

Is O35 a billable ICD-10-CM code?: No. O35 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does O35 sit in the tabular list?: Pregnancy, childbirth and the puerperium (O00-O9A), in the block Maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48).
What cannot be coded together with O35?: O35 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.