Pathology/Lab Coding Alert

Don’t miss double duty for biopsy specimen.

Patients with serious burns may require a range of clinical diagnostic testing and pathology examination performed by your lab to guide treatment protocols and optimize patient outcome.

Study the following case and use our experts’ tips to make sure you capture the procedure codes and diagnosis details you would need to accurately code the case.

Survey Case-Note Specifics

Patient: An 18-year-old male new patient presents with burns to his buttocks after falling into a campfire, including severe deep burns on most of the left buttock.

Specimen(s): The pathologist receives in one container, three punch biopsies through burn eschar into healthy tissue from the left buttock.

Procedures: The pathologist transfers some tissue from the punch biopsies to the microbiology lab, then performs a histologic exam of the remaining biopsy tissue with Gram stain and Hematoxylin and Eosin (H&E). The microbiology lab analyst swabs the tissue and smears a slide for Gram staining, then homogenizes and dilutes the remaining tissue, performing calibrated loop cultures to definitively identify and quantify the presence of bacteria in the specimen, including biochemical panels, genomic sequencing, and antibiotic susceptibility testing using minimum inhibitory concentration (MIC).

Findings: The pathologist reports the depth of burned tissue as full thickness extending into subcutaneous tissue, and identifies the presence of Gram positive bacteria. The microbiology lab immediately reports findings from the direct smear as Gram positive coccus bacteria appearing in grape-like clusters. Days later, the presumptive culture was positive for Staphylococcus. The lab definitively identifies the culture as Staphylococcus aureus, reporting a colony concentration of 109 bacteria per gram. The genomic sequencing of the isolate identified a methicillin-susceptible strain, and the MIC test indicated appropriate methicillin dosage for the organism.

Capture Procedure Codes

From the pathologist to the microbiology lab, this case involves several distinct procedures that you need to describe with appropriate CPT^® codes. Try your hand at the coding, then check your answers against our experts’.

Pathology services: “You should code one unit of 88305 (Level IV - Surgical pathology, gross and microscopic examination … Skin, other than cyst/tag/debridement/ plastic repair …) for the punch biopsy exam, and one unit of 88312 (Special stain including interpretation and report; Group I for microorganisms (eg, acid fast, methenamine silver)) for the Gram stain” says R.M. Stainton Jr., MD, president of Doctors’ Anatomic Pathology Services in Jonesboro, Ark. “Because the surgeon does not separately submit or identify the three punch biopsies, you should treat the tissue as one specimen,” he says.

Microbiology codes: You’ll need several codes to report the steps involved in the culture isolation, identification, and further analysis.

For the Gram stain on the direct smear, you should code 87205 (Smear, primary source with interpretation; Gram or Giemsa stain for bacteria, fungi, or cell types), according to William Dettwyler, MT AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore. “The lab immediately reports this finding to the clinician, who may want to start an antibiotic treatment before the final culture results are available,” he explains.

Report the quantitative aerobic culture and definitive identification using the following two codes:

• 87071 (Culture, bacterial; quantitative, aerobic with isolation and presumptive identification of isolates, any source except urine, blood or stool)
• 87077 (Culture, bacterial; aerobic isolate, additional methods required for definitive identification, each isolate)

Report the culture sequencing to rule out methicillin resistant Staphylococcus aureus (MRSA) as 87153 (Culture, typing; identification by nucleic acid sequencing method, each isolate (eg, sequencing of the 16S rRNA gene)).

Finally, capture the MIC testing by billing 87186 (Susceptibility studies, antimicrobial agent; microdilution or agar dilution (minimum inhibitory concentration [MIC] or breakpoint), each multi-antimicrobial, per plate).

Understand Burn Diagnosis Coding

Although the clinical lab wouldn’t assign an ICD-10 code, the pathology report and microbiology findings, along with the clinical information the surgeon provides, give the clinician a full picture to assign a final diagnosis for this case.

Burn coding: The burn is on the patient’s buttock, which reports to ICD-10 category T21 (Burn and corrosion of trunk). To assign the required 4th character for this code, you need to know the “degree” characterization of the burn, and whether the case involves a chemical or thermal burn.

Based on clinical observation and biopsy findings of the depth of the eschar, the physician can identify that this case involves third-degree burns.

ICD-10 differentiates between burns and corrosions, with the burn codes describing thermal burns caused by a heat source such as fire, electricity, or radiation, and the corrosion codes describing burns caused by chemicals.

“The ICD-10-CM guidelines are the same for both burns and corrosions,” says Caral Edelberg, CPC, CPMA, CAC, CCS-P, CHC, chief executive officer with Edelberg + Associates in Baton Rouge, La.

Because this case involves third-degree thermal burns, the appropriate 4th character for the ICD-10 code is “3,” bringing you to T21.3- (Burn of third degree of trunk).

That’s not all: You must report this code to the 7th character. The 5th character narrows down the burn site from “trunk” to “buttock.” Because ICD-10 doesn’t provide buttock laterality for the 6th character, coding requires an “X” placeholder before assigning the 7th character that describes the encounter as “A” for initial encounter.

The correct diagnosis code for the case is T21.35XA (Burn of third degree of buttock, initial encounter).

Don’t miss: These codes also require you to report additional external cause code to identify the source, place, and intent of the burn. Based on the surgeon’s description, an appropriate ICD-10 code would be X03.0XXA (Exposure to flames in controlled fire, not in building or structure, initial encounter).

Identify infection: Based on the other test results, the clinician should be able to report ICD-10 code(s) to document the infection, such as L08.89 (Other specified local infections of the skin and subcutaneous tissue) and B95.61 (Methicillin susceptible Staphylococcus aureus infection as the cause of diseases classified elsewhere).