Test Catalog

Test Id : CDIP

Corynebacterium diphtheriae Culture, Varies

Useful For
Suggests clinical disorders or settings where the test may be helpful

Confirmation of the clinical diagnosis of diphtheria

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test Id Reporting Name Available Separately Always Performed
RMALD Ident by MALDI-TOF mass spec No, (Bill Only) No
ISAE Aerobe Ident by Sequencing No, (Bill Only) No
REFID Additional Identification Procedure No, (Bill Only) No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Method Name
A short description of the method used to perform the test

Conventional Culture Technique

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

C. diphtheria Culture

Lists additional common names for a test, as an aid in searching

Culture, Corynebacterium diphtheria


Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Specimen Type
Describes the specimen type validated for testing


Necessary Information

Specimen source is required.


Question ID Description Answers
Q00M0012 Specimen Source

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Submit only 1 of the following specimens:



Specimen Type: Throat or pharynx

Supplies: Culturette (BBL Culture Swab) (T092)

Container/Tube: Culture transport swab (Dacron or rayon swab with aluminum or plastic shaft with either Stuart or Amies liquid medium)

Specimen Volume: Entire specimen

Additional information: A swab from beneath the pseudomembrane is preferred



Specimen Type: Nasopharyngeal swab

Supplies: Nasopharyngeal swab

Container/Tube: Rayon swab with an aluminum shaft placed in transport medium such as a green-top nasopharyngeal swab (rayon mini-tip) with Stuart's media

Specimen Volume: Entire specimen

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

See Specimen Required

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Varies Ambient (preferred) 24 hours
Refrigerated 24 hours

Useful For
Suggests clinical disorders or settings where the test may be helpful

Confirmation of the clinical diagnosis of diphtheria

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

When this test is ordered, the reflex tests may be performed at an additional charge.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Corynebacterium diphtheriae is the etiological agent of diphtheria and occurs in 2 forms, respiratory and cutaneous diphtheria. Respiratory diphtheria may be further classified into pharyngeal, tonsillar, laryngeal, and the less common anterior nasal diphtheria. Due to vaccination programs in the United States, diphtheria is now a rarely reported disease. Corynebacterium diphtheriae is primarily spread by droplets from coughing or sneezing. The incubation period averages 2 to 5 days. The illness is characterized by fever, malaise, and sore throat with a distinguishing thick pseudomembrane present over the involved mucosa. A swab from beneath the pseudomembrane is the preferred specimen for culture. The organisms multiplying at the infection site produce a toxin, diphtheria toxin, which may result in systemic complications affecting the heart, nervous system, etc.


In patients with a clinical diagnosis of possible diphtheria, appropriate specimens should be collected for culture; patients should be placed in appropriate isolation and consideration given to administration of empiric antitoxin (available in the United States through the Centers for Disease Control and Prevention) and antibiotics; respiratory and airway support may be required.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

No growth of Corynebacterium diphtheriae

Provides information to assist in interpretation of the test results

A positive result supports a diagnosis of diphtheria. The pathogenesis of the associated disease relates to production phage-encoded diphtheria toxin. Since isolates of Corynebacterium diphtheriae may or may not harbor genes to produce the toxin, they should be further tested for diphtheria toxin production. When isolated, other potentially toxin-producing organisms (eg, Corynebacterium ulcerans, Corynebacterium pseudotuberculosis) will also be reported.


A negative result is evidence against a diagnosis of diphtheria but does not definitively rule out this disease since culture may be negative because of prior antimicrobial therapy or organism present below the limit of detection of the assay.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

Procop GW, Hall GS, Janda WM, Koneman EW, Schreckenberger PC, Woods GL: Color Atlas and Textbook of Diagnostic Microbiology. 7th ed. In: Wolters Kluwer Health; 2017:890-896

Method Description
Describes how the test is performed and provides a method-specific reference

Culture is performed using sheep blood agar and the selective medium, cystine-tellurite blood agar, incubated at 35 degrees C in a CO2-enriched atmosphere. Colonies of Corynebacterium diphtheriae are gray-black on tellurite-containing agar, while usual oral flora is inhibited. Suspect colonies are identified by conventional methods to rule-out C diphtheriae. For Mayo Clinic patients or Mayo Clinic Laboratories clients from Minnesota, isolates identified as C diphtheriae are forwarded to the Minnesota Department of Health for toxin testing.(Synder JW: Corynebacterium diphtheriae Cultures. In: Leber, AL ed. Clinical Microbiology Procedures Handbook. 4th ed. American Society for Microbiology. 2016: section 3.11.7)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

3 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

2 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

87081-Corynebacterium diphtheriae culture

87077-Identification by MALDI-TOF mass spec (if appropriate)

87077-Additional identification procedure (if appropriate)

87153-Aerobe identification by sequencing (if appropriate)

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
CDIP C. diphtheria Culture 16676-9
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
CDIP C. diphtheria Culture 16676-9

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports