2025 CPT code 87181
(Active) Effective Date: N/A Susceptibility Studies - Microbiology Procedures Pathology and Laboratory Feed
Susceptibility studies, antimicrobial agent; agar dilution method, per agent (e.g., antibiotic gradient strip).
Modifiers 59 and 91 may be applicable as stated in the coding guidelines.
Medical necessity for 87181 is established when susceptibility testing is required to guide appropriate antimicrobial therapy for a documented infection.This is particularly important in cases of antibiotic resistance or when treatment failure is suspected.
Following the culture, isolation, and identification of a microorganism, a lab analyst inoculates an agar plate with the isolate. A test strip containing a concentration gradient of a specific antimicrobial agent is placed on the agar. After incubation, the analyst determines the minimum inhibitory concentration (MIC) where bacterial growth is inhibited.
In simple words: This test helps doctors figure out which antibiotic and what dose will best treat a bacterial infection. A lab technician places a strip with different concentrations of an antibiotic on a dish containing the bacteria. Where the bacteria stop growing indicates the lowest effective dose of the antibiotic.
This code represents a susceptibility study performed to evaluate the sensitivity of a bacterial isolate to a particular antimicrobial agent using the agar dilution method. In this method, a strip containing a gradient of antibiotic concentrations is placed on an agar plate that has been inoculated with the bacteria.The minimum inhibitory concentration (MIC) is then determined by observing the point on the strip where bacterial growth is inhibited.Each unit of 87181 represents the test for one antimicrobial agent.
Example 1: A patient presents with a complicated urinary tract infection. A urine culture is performed, and E. coli is isolated. To determine the most effective antibiotic, an 87181 is performed for several different antibiotics, including ampicillin, ciprofloxacin, and nitrofurantoin., A patient with a diabetic foot ulcer develops a severe infection.A culture reveals the presence of Methicillin-resistant Staphylococcus aureus (MRSA).87181 is used to test the susceptibility of the MRSA isolate to vancomycin, linezolid, and daptomycin to guide treatment decisions., A patient with pneumonia has a sputum culture positive for Streptococcus pneumoniae. To ensure appropriate antibiotic therapy, an 87181 is performed to test the susceptibility of the organism to penicillin, ceftriaxone, and levofloxacin.
Documentation should include the organism isolated, the antimicrobial agents tested, the method used (agar dilution), and the MIC results for each agent. The medical record should also reflect the clinical indication for the susceptibility testing.
- Revenue Code: T1H
- Specialties:Microbiology, Infectious Disease, Pathology
- Place of Service:Independent Laboratory, Hospital Laboratory