Test ID CFRCS Bacterial Culture, Cystic Fibrosis with Antimicrobial Susceptibilities, Varies
Shipping Instructions
Specimen must be received in laboratory within 48 hours of collection at refrigerated temperature. Specimens received frozen will be rejected.
For shipping information see Infectious Specimen Shipping Guidelines.
Necessary Information
Specimen source is required
Specimen Required
Submit only 1 of the following specimens:
Preferred:
Specimen Type: Sputum, expectorated or induced
Patient Preparation: Have the patient brush their teeth or gargle with water immediately prior to specimen collection. This reduces the number of contaminating oropharyngeal bacteria.
Container/Tube: Sterile container
Specimen Volume: Entire collection
Acceptable:
Specimen Type: Bronchial aspirate or washing, sinus aspirate, bronchoalveolar lavage, endotracheal, or tracheal
Container/Tube: Sterile container
Specimen Volume: Entire collection
Specimen Type: Throat swab
Supplies:
Culturette (BBL Culture Swab) (T092)
BD E-Swab (T853)
Container/Tube: Culture transport swab (Dacron or rayon swab with aluminum or plastic shaft with either Stuart or Amies liquid medium), or ESwab
Specimen Volume: Entire collection
Useful For
Detecting disease-causing aerobic bacteria in specimens from patients with cystic fibrosis
Determining the in vitro antimicrobial susceptibility of potentially pathogenic aerobic bacteria, if appropriate
Reflex Tests
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
COMM | Identification Commercial Kit | No, (Bill Only) | No |
RMALD | Ident by MALDI-TOF mass spec | No, (Bill Only) | No |
GID | Bacteria Identification | No, (Bill Only) | No |
ISAE | Aerobe Ident by Sequencing | No, (Bill Only) | No |
REFID | Additional Identification Procedure | No, (Bill Only) | No |
SALS | Serologic Agglut Method 1 Ident | No, (Bill Only) | No |
EC | Serologic Agglut Method 2 Ident | No, (Bill Only) | No |
SHIG | Serologic Agglut Method 3 Ident | No, (Bill Only) | No |
STAP | Identification Staphylococcus | No, (Bill Only) | No |
STRP | Identification Streptococcus | No, (Bill Only) | No |
MIC | Susceptibility, MIC | No, (Bill Only) | No |
SUS | Susceptibility | No, (Bill Only) | No |
SIDC | Ident Serologic Agglut Method 4 | No, (Bill Only) | No |
PCRID | Identification by PCR | No, (Bill Only) | No |
MARP1 | mecA PCR (Bill Only) | No, (Bill Only) | No |
Testing Algorithm
When this test is ordered, the reflex tests may be performed at an additional charge. Antimicrobial agent appropriate to the organism and specimen source will be tested according to Mayo Clinic's practice.
The following tables provide a listing of the antimicrobials routinely tested in the laboratory as well as antimicrobials that may be tested upon request. These tables are organized by isolate groups and are not all inclusive. Call 800-533-1710 and ask to speak to the Bacteriology Antimicrobial Susceptibility Testing Laboratory if the organism or antimicrobial of interest are not listed in these tables.
-Aerobic Gram-Negative Bacilli Antimicrobials
-Additional Gram-Negative Bacteria Antimicrobials
-Staphylococcus, Enterococcus, Bacillus, and Related Genera Antimicrobials
Special Instructions
Method Name
Conventional Culture Technique with Minimal Inhibitory Concentration (MIC) (Agar Dilution or Broth Microdilution or Gradient Diffusion) or Disk Diffusion (if appropriate)
Reporting Name
Bacterial Culture,Cystic Fib +SuscSpecimen Type
VariesSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Refrigerated | 48 hours |
Reference Values
No growth or usual microbiota
Identification of probable pathogens:
Susceptibility results are reported as minimal inhibitory concentration (MIC) in mcg/mL Breakpoints (also known as "clinical breakpoints") are used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, resistant or nonsusceptible according to breakpoint setting organizations, either the Clinical and Laboratory Standards Institute (CLSI) or the European Committee on Antimicrobial Susceptibility Testing (EUCAST), as applicable. In some instances, an interpretive category cannot be provided based on available data and the following comment will be included: "There are no established interpretive guidelines for agents reported without interpretations."
Clinical and Laboratory Standards Institute (CLSI) Interpretive Category Definitions:
Susceptible:
A category defined by a breakpoint that implies that isolates with an MIC at or below or a zone diameter at or above the susceptible breakpoint are inhibited by the usually achievable concentrations of antimicrobial agent when the dosage recommended to treat the site of infection is used, resulting in likely clinical efficacy.
Susceptible-Dose Dependent:
A category defined by a breakpoint that implies that susceptibility of an isolate depends on the dosing regimen that is used in the patient. To achieve levels that are likely to be clinically effective against isolates for which the susceptibility testing results (either MICs or zone diameters) are in the susceptible-dose dependent (SDD) category, it is necessary to use a dosing regimen (ie, higher doses, more frequent doses, or both) that results in higher drug exposure than that achieved with the dose that was used to establish the susceptible breakpoint. Consideration should be given to the maximum literature-supported dosage regimens because higher exposure gives the highest probability of adequate coverage of a SDD isolate. The drug label should be consulted for recommended doses and adjustment for organ function.
Intermediate:
A category defined by a breakpoint that includes isolates with MICs or zone diameters within the intermediate range that approach usually attainable blood and tissue levels and/or for which response rates may be lower than for susceptible isolates.
Note: The intermediate category implies clinical efficacy in body sites where the drugs are physiologically concentrated or when a higher-than-normal dosage of a drug can be used. This category also includes a buffer zone, which should prevent small, uncontrolled, technical factors from causing major discrepancies in interpretations, especially for drugs with narrow pharmacotoxicity margins.
Resistant:
A category defined by a breakpoint that implies that isolates with an MIC at or above or a zone diameter at or below the resistant breakpoint are not inhibited by the usually achievable concentrations of the agent with normal dosage schedules and/or that demonstrate MICs or zone diameters that fall in the range in which specific microbial resistance mechanisms are likely, and clinical efficacy of the agent against the isolate has not been reliably shown in treatment studies.
Nonsusceptible:
A category used for isolates for which only a susceptible breakpoint is designated because of the absence or rare occurrence of resistant strains. Isolates for which the antimicrobial agent MICs are above or the zone diameters are below the value indicated for the susceptible breakpoint should be reported as nonsusceptible.
Note: An isolate that is interpreted as nonsusceptible does not necessarily mean that the isolate has a resistance mechanism. It is possible that isolates with MICs above the susceptible breakpoint that lack resistance mechanisms may be encountered within the wild-type distribution after the time the susceptible-only breakpoint was set.
Epidemiological Cutoff Value:
The MIC that separates microbial populations into those with and without phenotypically detectable resistance (non-wild-type or wild-type, respectively). The epidemiological cutoff value (ECV) defines the highest MIC for the wildtype population of isolates. ECVs are based on in vitro data only, using MIC distributions. ECVs are not clinical breakpoints, and the clinical relevance of ECVs for a particular patient has not yet been identified or approved by CLSI or any regulatory agency.
When an ECV is reported, an interpretive category is not assigned, and the following comment will be included: "This MIC is consistent with the Epidemiological Cutoff Value (ECV) observed in isolates (WITH / WITHOUT) acquired resistance; however, correlation with treatment outcome is unknown."
Wild-type (WT) - an interpretive category defined by an ECV that describes the microbial population with no phenotypically detectable mechanisms of resistance or reduced susceptibility for an antimicrobial agent being evaluated.
Non-wild-type (NWT) - an interpretive category defined by an ECV that describes the microbial population with phenotypically detectable mechanisms of resistance or reduced susceptibility for the antimicrobial agent being evaluated.
Note: MIC values for which ECV's are defined are not to be interpreted or reported as susceptible, intermediate, or resistant but rather as WT or NWT. The ECV's should not be used as clinical breakpoints.(Clinical and Laboratory Standards Institute [CLSI]. Performance Standards for Antimicrobial Susceptibility Testing. 32nd ed. CLSI supplement M100. CLSI; 2022:4-6, 278-279)
European Committee on Antimicrobial Susceptibility Testing (EUCAST) Interpretive Category Definitions:
S - Susceptible, standard dosing regimen: A microorganism is categorized as "Susceptible, standard dosing regimen," when there is a high likelihood of therapeutic success using a standard dosing regimen of the agent
I - Susceptible, increased exposure*: A microorganism is categorized as "Susceptible, Increased exposure*" when there is a high likelihood of therapeutic success because exposure to the agent is increased by adjusting the dosing regimen or by its concentration at the site of infection.
R - Resistant: A microorganism is categorized as "Resistant" when there is a high likelihood of therapeutic failure even when there is increased exposure*.
*Exposure is a function of how the mode of administration, dose, dosing interval, infusion time, as well as distribution and excretion of the antimicrobial agent will influence the infecting organism at the site of infection.
(The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters. Version 12.0, 2022;6. Available at www.eucast.org)
Day(s) Performed
Report Available
4 to 12 daysPerforming Laboratory

Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
87070-Bacterial, Culture, cystic fibrosis, respiratory
87077-Identification commercial kit (if appropriate)
87077-Ident by MALDI-TOF mass spec (if appropriate)
87077-Bacteria Identification (if appropriate)
87077-Additional Identification procedure (if appropriate)
87077-Identification Staphylococcus (if appropriate)
87077-Identification Streptococcus (if appropriate)
87147 x 1-3-Serologic agglut method 1 ident (if appropriate)
87147-Serologic agglut method 2 ident (if appropriate)
87147 x 4-Serologic agglut method 3 ident (if appropriate)
87147 x 2-6-Serologic Agglut Method 4 Ident (if appropriate)
87153-Aerobe ident by sequencing (if appropriate)
87150-Identification by PCR (if appropriate)
87185-Beta lactamase (if appropriate)
87186-Antimicrobial Susceptibility, Aerobic Bacteria, MIC-per organism for routine battery (if appropriate)
87181-Susceptibility per drug and per organism for drugs not in routine battery (if appropriate)
87150-mec A PCR (if appropriate)
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
CFRCS | Bacterial Culture,Cystic Fib +Susc | 44798-7 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
CFRCS | Bacterial Culture,Cystic Fib +Susc | 44798-7 |
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.