Last reviewed: October 2026
The complete blood count (CBC) is one of the most-ordered lab tests, and one of the easiest to code wrong. The CPT code depends on whether a white blood cell differential was done and how, and Medicare pays only when the diagnosis supports the test. This guide covers the CBC CPT codes, CBC ICD-10 coding, point-of-care CBCs and the mistakes that cause denials.
What Is the CPT Code for a CBC?
85025 is the CPT code for an automated CBC with an automated white blood cell (WBC) differential. 85027 is the code for an automated CBC without a differential. Both include hemoglobin, hematocrit, red blood cell count, white blood cell count and platelet count.
| CPT code | What it covers | When to use it |
|---|---|---|
| 85025 | CBC, automated, with automated WBC differential | The order is “CBC with diff” and the analyzer performs the differential |
| 85027 | CBC, automated, without differential (often called a hemogram) | The order is “CBC” or “CBC without diff” |
| 85004 | Automated WBC differential only | A differential is ordered without a full CBC |
| 85007 | Blood smear, microscopic exam with manual WBC differential | A technologist counts the differential by hand |
| 85008 | Blood smear, microscopic exam without manual differential | A smear review without a manual count |
| 85048 | Automated WBC count only | Only a white count is ordered |
| 85049 | Automated platelet count only | Only a platelet count is ordered |
| 85014 / 85018 | Hematocrit / hemoglobin only | Only one of these is ordered |
CBC With Differential vs. Without Differential
A differential breaks the white blood cell count into neutrophils, lymphocytes, monocytes, eosinophils and basophils. It’s ordered when the provider is looking for infection, inflammation, allergic reaction or a blood disorder.
- Automated differential: bill 85025 alone. Don’t add 85004; the differential is already included.
- No differential: bill 85027.
- Manual differential instead of automated: bill 85027 plus 85007, not 85025.
Code what was ordered and performed. If the order says “CBC” and the analyzer reports a differential the provider didn’t ask for, most payers expect 85027.
CBC ICD-10 Codes: Which Diagnosis Supports a CBC?
There’s no ICD-10 code for a CBC itself. The ICD-10 code on the claim is the reason the provider ordered the test, taken from the order. These are diagnoses commonly linked to a CBC:
| ICD-10 code | Description |
|---|---|
| D64.9 | Anemia, unspecified |
| D50.9 | Iron deficiency anemia, unspecified |
| D69.6 | Thrombocytopenia, unspecified |
| D72.829 | Elevated white blood cell count, unspecified |
| R50.9 | Fever, unspecified |
| R53.83 | Other fatigue |
| Z79.899 | Other long-term (current) drug therapy (monitoring drugs that affect blood counts) |
| Z01.812 | Encounter for preprocedural laboratory examination |
| Z13.0 | Encounter for screening for diseases of the blood and blood-forming organs |
| Z00.00 / Z00.01 | General adult medical exam without / with abnormal findings |
Medicare rules: Medicare covers CBCs under National Coverage Determination (NCD) 190.15, Blood Counts. A CBC on a patient with no signs, symptoms or condition that could affect blood counts is screening, and Medicare doesn’t cover it, so Z13.0 and the Z00 codes won’t support a Medicare CBC. If the patient wants the test anyway, get a signed Advance Beneficiary Notice (ABN) before the draw and add modifier GA. Repeat CBCs need a reason, such as abnormal results or a change in the patient’s condition, and the claim should carry the more specific diagnosis. Commercial plans often cover a CBC with a preventive visit; check the plan.
Point-of-Care CBC Billing
A point-of-care CBC is run on an analyzer in the office or clinic instead of being sent to a lab. It uses the same CPT codes (85025 or 85027), but the office needs the right CLIA certificate:
- Most CBC analyzers are moderate complexity, so the office needs a CLIA certificate of compliance or accreditation.
- A few CBC analyzers are CLIA-waived. To run them under a certificate of waiver, check the device in the FDA’s CLIA database and add the QW modifier if Medicare requires it for that code.
- The CLIA number goes in item 23 of the CMS-1500 (loop 2300, REF X4 on electronic claims).
Claims for tests outside the office’s CLIA certificate are denied, so check the certificate before adding a new analyzer to your billing.
Common CBC Billing Mistakes
- Billing 85025 when no differential was ordered or performed.
- Billing 85025 with a manual differential: use 85027 plus 85007.
- Adding 85004 to 85025: the differential is already in 85025.
- Screening diagnoses on Medicare claims without an ABN.
- A diagnosis that doesn’t match the order: the lab can’t add a reason the provider didn’t document.
- A CLIA certificate that doesn’t cover the analyzer, or a missing QW modifier.
If your office collects the specimen, bill the blood draw separately as 36415 (routine venipuncture). See our guide to the CPT code for a lab draw.
Example: Billing a CBC With Differential
A patient with fever and fatigue sees their provider, who orders a CBC with differential. The office draws the blood and runs the CBC on a moderate-complexity analyzer. The claim:
- 85025 (CBC with automated differential), linked to R50.9 and R53.83
- 36415 (venipuncture)
- The office’s CLIA number in item 23
Lab billing has more of these rules than most specialties. Our laboratory billing services handle coding, CLIA and ABN checks, claims and denials for labs and physician office labs. For the full workflow, see our guide to the laboratory billing process.
FAQs
What is the CPT code for a CBC with differential?
85025, for an automated CBC with an automated differential. If the differential is done manually, bill 85027 plus 85007.
What is the CPT code for a CBC without differential?
85027. It covers the automated CBC (hemoglobin, hematocrit, RBC, WBC and platelet count) without breaking down the white cells.
What ICD-10 code do I use for a CBC?
There’s no ICD-10 code for the CBC itself. Use the diagnosis that explains why the provider ordered it, such as D64.9 (anemia, unspecified) or R50.9 (fever, unspecified).
Does Medicare cover a screening CBC?
No. Under NCD 190.15, a CBC for a patient with no signs, symptoms or related condition is screening and isn’t covered. Get an ABN if the patient wants the test.
Can I bill 36415 with a CBC?
Yes, when your office or lab draws the blood. Don’t bill it if the specimen was collected somewhere else.
1 Comment