Pathology/Lab Coding Alert

Avoid ‘unspecified’ codes -- choose test’s ‘reason’ instead.

Whether you code for a clinical lab or a pathology practice, making sure your claims have the right ICD-9 code can be the key to documenting the patient’s medical condition -- and to payment. That’s why you need to follow our experts’ advice to cut through confusing options and make sure you know how to choose the correct ICD-9 codes for your claims.

Tip 1: Use ‘Ordering Diagnosis’ for Clinical Labs

If you’re billing for a clinical laboratory, you won’t be assigning a diagnosis based on lab test results. "Instead, you’ll use the diagnosis code that the physician assigns when ordering the test," says William Dettwyler, MTAMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore.

Here’s why: Clinical lab test results are only one component of determining a diagnosis for a patient’s condition. The treating physician will account for the lab test findings, as well as the patient’s history and clinical presentation, when assigning an ICD-9 code.

In fact, CMS rules require you to use the referring physician’s clinical diagnosis as the principal diagnosis on your claim form.

That means you’ll often report signs or symptoms that prompted the physician to order a lab test. If the ordering physician provides a narrative diagnosis instead of assigning a code, you need to be ready to determine the ICD-9 code yourself, based on the physician’s description.

For example: A patient presents with fatigue, and the treating physician orders a complete blood count (CBC). The CBC results indicate low counts for hematocrit and hemoglobin, indicating that the patient is anemic.

Solution: If the physician provided a narrative description (fatigue) but didn’t assign an ICD-9 code, the lab should assign one using the reason the physician ordered the test: 780.79

(Other malaise and fatigue). As a coder for a clinical lab, you should not assign a diagnosis based on findings, such as 285.9 (Anemia unspecified). The patient’s physician will assign a diagnosis based on the lab test results and any other relevant clinical factors.

Tip 2: Assign Definitive Diagnosis from Pathology Report

When a pathologist examines a tissue or cytology specimen and diagnoses a condition, you should assign the ICD-9 code for that condition. That’s different than results for clinical lab tests, which you don’t use to assign a diagnosis.

Here’s why: Unlike lab test results, the pathologist provides a physician service in determining the diagnosis based on a tissue or cytology exam or other professional interpretation. Reporting the pathologist’s diagnosis follows ICD-9 coding guidelines to report the most specific diagnosis.

Caveat: Using the most definitive diagnosis assumes that you have access to the pathology report at the time of billing  and that is preferable when billing for pathology practices.

Example: The treating physician submits a specimen identified as "skin lesion, left arm." The pathologist examines the specimen (88305, Level IV - Surgical pathology, gross and microscopic examination, Skin, other than cyst/tag/debridement/plastic repair) and diagnoses squamous cell carcinoma.

"You should code the pathologist’s definitive diagnosis," says R.M. Stainton Jr., MD, president of Doctors’ Anatomic Pathology Services in Jonesboro, Ark. In this case, that means reporting 173.62 (Squamous cell carcinoma of skin of upper limb, including shoulder), not a non-specific code based on the ordering physician’s documentation of a "skin lesion."

Tip 3: Revert to Ordering Dx for Non-Specific Pathology Findings

Sometimes the pathology report indicates non-specific findings, or even "normal" tissue -- what should you do in those cases?

Answer: Revert to the ordering diagnosis, even if that’s signs and symptoms.

For example: The pathologist examines thin layer preparation slides from a peritoneal fluid aspiration specimen for a patient with hepatitis C. The pathologist diagnoses "negative for malignant cells" and includes diagnostic comments noting lymphoid cells, histocytes, and mesothelial cells.

Solution: Report the pathologist’s work as 88112 (Cytopathology, selective cellular enhancement technique with interpretation [e.g., liquid based slide preparation method], except cervical or vaginal). Because the pathology report lists non-specific "normal" findings, you should use the ordering diagnosis to assign the ICD-9 code -- 070.70 (Unspecified viral hepatitis c without hepatic coma).

Pitfall: When the pathologist reports "negative for malignant cells," coders are often tempted to choose a "benign" code or a "non-specific" code -- but that’s a rookie move.

In this example, you should not report 792.2 (Other nonspecific abnormal findings in body substances, peritoneal fluid) or 211.8 (Benign neoplasm of retroperitoneum and peritoneum) as the diagnosis code.

Bottom line: "When the pathology report indicates normal findings, you should assign the ICD-9 code based on the diagnosis from the ordering physician," Dettwyler says.