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HelpTest Code KKBRP Kingella kingae, Molecular Detection, PCR, Blood
Useful For
Aiding in the diagnosis of Kingella kingae infection using whole blood specimens
Method Name
Real-Time Polymerase Chain Reaction (PCR)
Reporting Name
Kingella kingae PCR, BSpecimen Type
Whole Blood EDTASpecimen Required
The high sensitivity of amplification by polymerase chain reaction requires the specimen to be processed in an environment in which contamination of the specimen by Kingella kingae DNA is unlikely.
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Royal blue top (EDTA), pink top (EDTA), or sterile vial containing EDTA-derived aliquot
Specimen Volume: 1 mL
Collection Instructions: Send specimen in original tube (preferred).
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Kingella kingae is a fastidious short gram-negative bacillus that may colonize the oropharynx of young children. Colonization may occasionally lead to invasive disease via hematogenous dissemination, primarily in children younger than 4 years of age. This most commonly results in bone and joint infection; K kingae is the most frequent cause of osteomyelitis and septic arthritis in children aged 6 to 36 months. K kingae may also cause endocarditis, involving both native and prosthetic valves, in patients of any age and is considered part of the HACEK (Haemophilus species, Aggregatibacter species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species) group of organisms, known for causing culture-negative endocarditis. K kingae produces a repeat-in-toxin (RTX) toxin.
Diagnosis of K kingae infection may be challenging due to the fastidious nature of the organism in culture. Evaluation of blood by polymerase chain reaction is a useful tool for the diagnosis of some cases of K kingae infection.
Reference Values
Not applicable
Interpretation
A positive result indicates the presence of Kingella kingae DNA.
A negative result indicates the absence of detectable K kingae DNA, but it does not negate the presence of the organism and may occur due to inhibition of polymerase chain reaction, sequence variability underlying primers or probes, or the presence of K kingae DNA in quantities less than the limit of detection of the assay.
Cautions
Test results should be used as an aid in diagnosis. A single assay should not be used as the only criteria to form a clinical conclusion, but results should be correlated with patient symptoms and clinical presentation. A negative result does not negate the presence of the organism or active disease.
This assay does not detect species of Kingella other than kingae or negevensis (see Supportive Data).
This assay cross-reacts with Kingella negevensis.(1)
Supportive Data
This assay was validated by testing 30-spiked positive ETDA whole blood samples and 10-negative samples. No PCR inhibitors were encountered. The assay was 100% sensitive and specific. The assay showed no cross-reactivity when tested with a panel of 67 bacterial isolates, including Kingella species other than kingae. The limit of detection in EDTA-whole blood was 1.3 CFU/mcL.
Method Description
Nucleic acid is extracted from the specimen using the automated MagNA Pure instrument. Target specific primers are used to amplify the rxtB gene region of Kingella kingae; amplification is monitored by detecting fluorescence produced by target specific fluorescence resonance energy transfer hybridization probes. This real-time polymerase chain reaction (PCR) takes place on a LightCycler instrument. Detection of the K kingae target is performed through melting curve analysis using the LightCycler software.(Cockerill FR, Uhl JR: Applications and challenges of real-time PCR for the clinical microbiology laboratory. In: Reischl U, Wittwer C, Cockerill F, eds. Rapid Cycle Real-Time PCR Methods and Applications. Springer-Verlag, 2002:3-27; Zbinden R: Aggregatibacter, Capnocytophaga, Eikenella, Kingella, Pasteurella, and other fastidious or rarely encountered gram-negative rods. In: Carroll KC, Pfaller M, eds. Manual of Clinical Microbiology. 12th ed. ASM Press; 2019:656-669)
Day(s) Performed
Monday through Friday
Report Available
2 to 7 daysSpecimen Retention Time
1 weekPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
87798
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| KKBRP | Kingella kingae PCR, B | 65809-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 48451 | Specimen Source | 31208-2 |
| 48338 | Kingella kingae PCR, B | 65809-6 |