Comparison of a commercial enzyme-linked immunosorbent assay with immunofluorescence and complement fixation tests for detection of Coxiella burnetii (Q fever) immunoglobulin M.
A commercially available enzyme-linked immunosorbent assay (ELISA) for the diagnosis of Q fever (PanBio Coxiella burnetii immunoglobulin M [IgM] ELISA, QFM-200) was compared to the indirect fluorescent antibody test (IFAT) for C. burnetii IgM and the complement fixation test (CFT). The ELISA demonstrated 92% agreement with the reference method (IFAT), and gave a sensitivity of 99% (69 of 70 samples) and a specificity of 88% (106 of 121). Specificity can be increased with confirmation by IFAT. CFT was found to have a specificity of 90% (107 of 119), although it was lacking in sensitivity (73%; 51 of 70). No cross-reactivity was observed in the ELISA with serum samples from patients with mycoplasma (n = 6), chlamydia (n = 5), or legionella (n = 4) infections, although 2 of 5 patients with leptospirosis and 1 of 4 samples containing rheumatoid factor (RF) demonstrated positive results in the ELISA. Results indicate that the performance of the PanBio C. burnetii (Q fever) IgM ELISA (F = 187) is superior to that of CFT (F = 163), and consequently the ELISA should be a useful aid in the diagnosis of acute Q fever.
Field
P R
PR
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, Westmead, Australia.
Mitchell
J L
JL
Santiago
A
A
Dickeson
D J
DJ
Chan
S W
SW
Ho
D W
DW
Murphy
A M
AM
Cuzzubbo
A J
AJ
Devine
P L
PL
D000907:Antibodies, Bacterial / Q000097:blood; D003168:Complement Fixation Tests; D016997:Coxiella burnetii / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D011778:Q Fever / Q000175:diagnosis* / Q000382:microbiology; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial; D007075:Immunoglobulin M