Kingella kingae, Molecular Detection, PCR, Blood

Casandra

Casandra Test Code MC33244Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID KKBRPCPT Code 87798

Kingella kingae, Molecular Detection, PCR, Blood

Clinical Use

Use

Aiding in the diagnosis of Kingella kingae infection using whole blood specimens. Kingella kingae is a fastidious gram-negative bacillus that may colonize the oropharynx of young children and cause invasive disease via hematogenous dissemination, commonly resulting in osteomyelitis and septic arthritis in children aged 6 to 36 months; it may also cause endocarditis in patients of any age and is part of the HACEK group. PCR detection of Kingella kingae DNA in blood offers a useful diagnosis when culture may fail. A positive result indicates presence of K. kingae DNA; a negative result does not rule out infection because of PCR inhibition, sequence variability, or low DNA quantity. PCR may cross‑react with Kingella negevensis. Supportive data include validation in spiked blood samples with high sensitivity and specificity and a limit of detection of approximately 1.3 CFU/µL.

Special Instructions

The assay uses real‑time PCR targeting the rtxB gene region, with fluorescence resonance energy transfer hybridization probes and melting curve analysis on a LightCycler instrument. Nucleic acid is extracted by the automated MagNA Pure instrument. Clinical data validation sources include references such as Cockerill & Uhl (2002) and Zbinden (2019). NY State availability is Yes.

Limitations

Negative results do not negate infection due to possible PCR inhibition, primer/probe mismatches, or low DNA quantities. The assay does not detect Kingella species other than kingae or negevensis and cross-reacts with K. negevensis. Clinical interpretation should not rely solely on this assay, but correlate with patient symptoms and clinical presentation.

Test Details

New York Approved