How To Use CPT Code 87181

CPT 87181 describes the process of conducting susceptibility studies, specifically using the agar dilution method, to determine the effectiveness of antimicrobial agents. This article will cover the official description, procedure, qualifying circumstances, appropriate usage, documentation requirements, billing guidelines, historical information, similar codes and billing examples.

1. What is CPT Code 87181?

CPT 87181 can be used to describe the performance of susceptibility studies using the agar dilution method. This method involves testing the effectiveness of specific antimicrobial agents, such as antibiotics, against a culture isolate. The lab analyst applies a test strip with a concentration gradient of the antimicrobial agent onto an agar plate inoculated with the isolate. The plate is then incubated, and the lab analyst reads the minimum inhibitory concentration (MIC) from the test strip to determine the organism’s susceptibility to the agent.

2. Official Description

The official description of CPT code 87181 is: ‘Susceptibility studies, antimicrobial agent; agar dilution method, per agent (e.g., antibiotic gradient strip).’ This code represents the performance of susceptibility studies using the agar dilution method for one specific antimicrobial agent.

3. Procedure

1. The lab analyst cultures, isolates, and identifies the organism to be tested.
2. A fresh agar plate is inoculated with the culture isolate.
3. A test strip with a concentration gradient of the specific antimicrobial agent is applied to the agar surface.
4. The plate is incubated for a specific time period.
5. The lab analyst reads the MIC from the test strip, which indicates the concentration at which the antimicrobial agent inhibits the growth of the organism.

4. Qualifying circumstances

CPT 87181 is typically ordered by clinicians to aid in the selection of an appropriate antibiotic and dosage level for treating an infection caused by the isolated organism. The lab analyst performs the susceptibility study using the agar dilution method to determine the organism’s susceptibility to the specific antimicrobial agent. The results are reported in mcg/mL, and the lab analyst may interpret the result into categories of susceptibility, intermediate, or resistance.

5. When to use CPT code 87181

CPT code 87181 should be used when conducting susceptibility studies using the agar dilution method for a specific antimicrobial agent. It is appropriate to use this code when the lab analyst performs the test to evaluate the organism’s susceptibility to the agent and provide valuable information for selecting the appropriate treatment.

6. Documentation requirements

To support a claim for CPT 87181, the documentation should include:

• Identification of the organism and the need for susceptibility testing
• Description of the specific antimicrobial agent used
• Date of the test and the incubation period
• Reading of the MIC from the test strip
• Interpretation of the result into susceptibility categories
• Signature of the lab analyst performing the test

7. Billing guidelines

When billing for CPT 87181, ensure that the test is performed using the agar dilution method for a specific antimicrobial agent. It is important to report this code accurately to reflect the performance of susceptibility studies. There are no specific guidelines regarding reporting this code with other codes.

8. Historical information

CPT 87181 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 using the agar dilution method to determine the effectiveness of an antibiotic against a culture isolate.
2. The test strip indicates a minimum inhibitory concentration (MIC) of 4 mcg/mL, indicating that the organism is susceptible to the antibiotic at a therapeutic dosage.
3. Another lab analyst conducts a susceptibility study using the agar dilution method for a different antimicrobial agent to evaluate its effectiveness against a culture isolate.
4. The test strip shows an MIC of 16 mcg/mL, indicating that the organism is resistant to the antimicrobial agent.
5. A clinician orders a susceptibility study using the agar dilution method to guide the selection of an appropriate antibiotic for treating a patient’s infection.
6. The lab analyst performs the test and reports the MIC as 8 mcg/mL, suggesting that the organism is susceptible to the antibiotic at a therapeutic dosage.
7. Another susceptibility study using the agar dilution method is conducted to determine the effectiveness of an antimicrobial agent against a culture isolate.
8. The test strip reveals an MIC of 32 mcg/mL, indicating that the organism is resistant to the antimicrobial agent.
9. A lab analyst performs a susceptibility study using the agar dilution method for a specific antimicrobial agent to assess its effectiveness against a culture isolate.
10. The test strip shows an MIC of 2 mcg/mL, indicating that the organism is susceptible to the antimicrobial agent at a therapeutic dosage.