How To Use CPT Code 87190

CPT 87190 describes the process of conducting susceptibility studies for mycobacteria using the proportion method. This article will cover the description, procedure, qualifying circumstances, appropriate usage, documentation requirements, billing guidelines, historical information, similar codes and billing examples.

1. What is CPT Code 87190?

CPT 87190 can be used to describe the susceptibility studies performed on mycobacteria using the proportion method. This code is used when a lab analyst evaluates the sensitivity of a mycobacteria culture isolate to an antimicrobial agent, commonly known as an antibiotic. The proportion method involves preparing agar plates with and without the antimicrobial agent, inoculating the plates with a specific dilution of the mycobacteria culture isolate, and counting the colonies on each plate to determine the ratio of resistant colonies to total colonies.

2. Official Description

The official description of CPT code 87190 is: ‘Susceptibility studies, antimicrobial agent; mycobacteria, proportion method, each agent.’ This code specifically applies to the evaluation of mycobacteria culture isolates using the proportion method. It should not be confused with other codes that describe susceptibility studies for different microorganisms or using different methods.

3. Procedure

1. Following the cultivation and isolation of a mycobacterium from a patient specimen, the lab analyst prepares agar plates containing the antimicrobial agent and agar plates without the agent.
2. The lab analyst inoculates the plates with a specific dilution of the mycobacteria culture isolate.
3. After incubating the plates for a specific period, the lab analyst counts the colonies on the plates with and without the antimicrobial agent.
4. The lab analyst calculates the ratio of resistant colonies on the antibiotic medium to colonies on the nutrient medium.
5. The lab analyst compares the test ratio to an established threshold for the specific antimicrobial agent to determine if the mycobacteria culture isolate is sensitive or resistant to the agent.
6. The lab analyst reports the susceptibility results to the clinician.

4. Qualifying circumstances

CPT 87190 is used when conducting susceptibility studies on mycobacteria culture isolates. This code applies to cases where the mycobacterium is being tested for its sensitivity or resistance to a specific antimicrobial agent. The test is typically ordered by clinicians to aid in the selection of an appropriate antibiotic for treating mycobacterial infections, such as tuberculosis (TB). The lab analyst must follow the proportion method and use agar plates with and without the antimicrobial agent to determine the resistance ratio.

5. When to use CPT code 87190

CPT code 87190 should be used when conducting susceptibility studies on mycobacteria culture isolates using the proportion method. This code is appropriate when evaluating the sensitivity or resistance of the mycobacterium to a specific antimicrobial agent. It should not be used for susceptibility studies on other microorganisms or when using different methods.

6. Documentation requirements

To support a claim for CPT 87190, the lab analyst must document the following information:

• Patient’s diagnosis or reason for conducting the susceptibility study
• Specific antimicrobial agent tested
• Description of the proportion method used
• Date of the study
• Results of the susceptibility study, including the resistance ratio
• Signature of the lab analyst performing the study

7. Billing guidelines

When billing for CPT 87190, ensure that the susceptibility study is conducted on mycobacteria culture isolates using the proportion method. This code should not be reported for susceptibility studies on other microorganisms or when using different methods. There are no specific guidelines regarding reporting CPT 87190 with other codes. However, it is important to accurately report the services provided and follow any applicable payer guidelines or policies.

8. Historical information

CPT 87190 was added to the Current Procedural Terminology system on January 1, 1990. There have been no updates or changes to the code since its addition.

9. Examples

1. A lab analyst performs a susceptibility study on a mycobacteria culture isolate to determine its sensitivity to rifampicin.
2. Using the proportion method, the lab analyst prepares agar plates with and without an antimicrobial agent and inoculates them with a specific dilution of the mycobacteria culture isolate.
3. After incubation, the lab analyst counts the colonies on each plate and calculates the resistance ratio.
4. Based on the established threshold, the lab analyst determines that the mycobacteria culture isolate is resistant to rifampicin.
5. The lab analyst reports the susceptibility results to the clinician, who can then select an appropriate antibiotic for treating the patient’s mycobacterial infection.