ARUP's Laboratory Test Directory

Antimicrobial Susceptibility - MIC/MBC : 0060203

Mnemonic: MA MBC

Methodology: Broth Microdilution
Performed: Sun-Sat
Reported: 2-4 days
Specimen Required: Collect: 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.

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

Unacceptable Conditions: Mixed cultures or non-viable organisms.

Stability (collection to initiation of testing): Ambient: 1 week; Refrigerated: Unacceptable; Frozen: Unacceptable

Reference Interval:
Susceptible, intermediate, or resistant.
Note: 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.

The MBC is defined as the lowest concentration of an antimicrobial agent needed to kill 99.9% 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 available to interpret the results.

For serious infections with coagulase-negative staphylococci, testing for the presence of mecA will be performed in order to interpret the results for 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 handling fee will be billed for all organisms submitted that are not in pure culture as indicated in the specimen requirements.
CPT Code(s): 87186; 87187
Cross References: Antibiotic MIC/MBC (Antimicrobial Susceptibility - MIC/MBC), MIC/MBC (Antimicrobial Susceptibility - MIC/MBC), Minimum Inhibitory Concentration (MIC)/Minimum Bactericidal Concentration (MBC) (Antimicrobial Susceptibility - MIC/MBC)