Ordering Recommendation

Determine the minimum bactericidal concentration (MBC) of requested antimicrobial agent against submitted bacterial isolate.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Actively growing isolate in pure culture.

Specimen Preparation

Transport sealed container with pure culture on agar slant or in bacterial transport media.  Place each specimen in individually sealed bag.

Storage/Transport Temperature

Room temperature.

Unacceptable Conditions

Mixed cultures or non-viable organisms.


Isolate identification and specimen source required. Individual antibiotics must be specified.


Ambient: 1 week; Refrigerated: Unacceptable; Frozen: Unacceptable


Broth Microdilution




2-6 days

Reference Interval

Susceptible, intermediate, or resistant.

Interpretive Data

Compliance Category

Depends on Specimen/Source/Method


The MBC is defined as the lowest concentration of an antimicrobial agent needed to kill 99.9 percent of the initial organism inoculum. Presently, specific guidelines for interpretation are not available; therefore, a clinician knowledgeable in both bactericidal testing and infectious diseases should be consulted to interpret the results.

The MIC is defined as the lowest concentration of an antibiotic which will inhibit the in vitro growth of an infectious organism. Results are reported in micrograms per mL. The interpretation of in vitro data is based on achievable serum concentrations, which may vary depending on dose, route of administration, degree of protein binding, site of infection, age and weight of the patient, and other factors.

For serious infections with coagulase-negative staphylococci, testing for oxacillin resistance will be performed in order to interpret the results for beta-lactam agents.

This test must be ordered for each antimicrobial agent tested.

The minimum turnaround time is 48 hours for nonfastidious, rapidly growing organisms and greater than or equal to 96 hours for fastidious, slow growing organisms.

An additional processing fee will be billed for all organisms submitted that are not in pure culture as indicated in the specimen requirements.

If species identification is not provided, identification will be performed at ARUP. Additional charges apply.

Hotline History


CPT Codes

87186; 87187


Component Test Code* Component Chart Name LOINC
0060203 Susceptibility, MIC/MBC 23658-8
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Antibiotic MBC
  • MBC
  • Minimum Bactericidal Concentration
  • Minimum Bactericidal Concentration (MBC)
Antimicrobial Susceptibility - MBC