Confirmation of the clinical diagnosis of diphtheria
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 |
When this test is ordered, the reflex tests may be performed at an additional charge.
Conventional Culture Technique
Culture, Corynebacterium diphtheria
Pseudomembrane
When this test is ordered, the reflex tests may be performed at an additional charge.
Varies
Specimen source is required.
Question ID | Description | Answers |
---|---|---|
Q00M0012 | Specimen Source |
Submit only 1 of the following specimens:
Preferred:
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
Acceptable:
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
See Specimen Required
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | 24 hours | |
Refrigerated | 24 hours |
Confirmation of the clinical diagnosis of diphtheria
When this test is ordered, the reflex tests may be performed at an additional charge.
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.
No growth of Corynebacterium diphtheriae
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.
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
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)
Monday through Sunday
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.
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)
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 |