ICD-10 code Z00.00 is one of the most frequently reported diagnosis codes in primary care, because it covers the everyday annual physical. But its billing rules trip up coders constantly — especially the line between Z00.00 and Z00.01, and how preventive visits interact with problems found during the exam.
What is ICD-10 code Z00.00?
Z00.00 is defined as: “Encounter for general adult medical examination without abnormal findings.” It falls in the Z00–Z13 range of the ICD-10-CM that covers encounters for examinations — visits where the patient has no complaint and the purpose is routine health assessment.
You report Z00.00 when an adult presents for a routine general physical and the provider finds nothing abnormal. It’s a “Z code,” meaning it describes a reason for the encounter rather than a disease. For more on how these codes fit the wider system, see how ICD-10 codes are structured.
Z00.00 vs Z00.01: the critical distinction
These two codes are identical except for one word:
- Z00.00 — general adult exam without abnormal findings.
- Z00.01 — general adult exam with abnormal findings.
If the provider discovers any abnormal finding during the routine exam — elevated blood pressure, an abnormal lab, a new lump — you must switch to Z00.01 and additionally code the abnormal finding. Reporting Z00.00 when an abnormality was found is a coding error.
Example: A patient comes in for an annual physical. The provider notes newly elevated blood pressure. You report Z00.01 (exam with abnormal findings) plus the appropriate hypertension code — not Z00.00.
Sequencing: Z00.00 as the first-listed code
On a routine preventive visit, Z00.00 (or Z00.01) is the first-listed (primary) diagnosis because the exam itself is the reason for the encounter. Any incidental findings are coded as additional diagnoses after it.
Pairing Z00.00 with the right CPT codes
Z00.00 supports preventive medicine E/M services, not problem-oriented visits. It typically pairs with the preventive CPT codes:
- 99385–99387 — new patient preventive visits by age.
- 99395–99397 — established patient preventive visits by age.
Do not pair Z00.00 with a problem-oriented office visit like 99213 as the sole diagnosis — that mismatch invites a denial. If a significant problem is addressed during the same visit, a separate problem-oriented E/M with Modifier 25 may be reported alongside the preventive service, each linked to its own diagnosis.
Avoiding common Z00.00 denials
- Wrong code after an abnormal finding. Using Z00.00 when the exam revealed an abnormality causes a diagnosis mismatch — switch to Z00.01.
- Preventive vs problem confusion. Billing a preventive diagnosis with a problem-oriented CPT (or vice versa) breaks medical necessity and can trigger CO-11 or CO-50.
- Missing additional codes. When you use Z00.01, you must also report the abnormal finding.
- Coverage limits. Many plans cover one preventive exam per period; verify with benefits verification before the visit.
Finding the code correctly
To confirm Z00.00 is the right choice, locate the reason for the encounter in the ICD-10 alphabetic index (look under “Examination”) and verify it in the Tabular List. For routine encounters like this, cross-reference related Z-codes such as the Z76.0 medication-refill code when the visit purpose differs. The full 2026 ICD-10-CM code list reflects the current guidelines.
Frequently Asked Questions
When should I use ICD-10 code Z00.00?
Use Z00.00 when an adult presents for a routine general medical examination and the provider finds no abnormal findings. It is reported as the first-listed diagnosis for a preventive visit.
What is the difference between Z00.00 and Z00.01?
Z00.00 is a general adult exam without abnormal findings; Z00.01 is the same exam with abnormal findings. If the provider discovers any abnormality during the routine exam, you must use Z00.01 and also code the abnormal finding.
What CPT codes go with Z00.00?
Z00.00 supports preventive medicine E/M codes — 99385–99387 for new patients and 99395–99397 for established patients, by age. It should not be the sole diagnosis on a problem-oriented visit code.
Can I bill a problem visit and a preventive visit on the same day as Z00.00?
Yes, when a significant separate problem is addressed. Report the preventive service with Z00.00 (or Z00.01) and a separate problem-oriented E/M with Modifier 25, each linked to its own diagnosis and supported by documentation.
