Alternative Lab Tests May Not Reliably Diagnose Lyme Disease

Laurie Barclay, MD

June 25, 2015

Detailed clinical and laboratory evaluation cannot distinguish alternatively diagnosed chronic Lyme syndrome (ADCLS) diagnosed by alternative laboratory methods from chronic fatigue syndrome (CFS), according to a case-control study published online June 16 in Clinical Infectious Diseases.

The investigators note that symptoms of ADCLS are often similar to those of CFS, and that the incidence of Lyme disease is low in British Columbia, where the study took place.

"Amongst patients reporting a diagnosis of Lyme disease, we observe four distinct groups, largely differentiated by the method of diagnosis," write David M. Patrick, MD, from the School of Population and Public Health, University of British Columbia, and the British Columbia Centre for Disease Control, both in Vancouver, Canada, and colleagues. "One of these is the controversial category of [ADCLS], in which diagnoses are made on clinical grounds supported not by testing at a regional reference laboratory, but rather by western blot testing performed at an American non-reference Lyme specialty laboratory (Lab A). Such tests have been the subject of warnings with respect to their accuracy, offer no benefit in finding Lyme disease when it is present, and may produce false positive results for more than 50% of people without Lyme disease who are tested."

The investigators compared 13 cases with ADCLS, of whom 12 were diagnosed by one alternative US laboratory; 25 cases with CFS; 25 matched healthy controls; and 11 controls with systemic lupus erythematosus. Measurements included history and physical examination, screening laboratory tests, seven functional scales, reference serology for Lyme disease using CDC criteria, reference serology for other tick-associated pathogens, and cytokine expression studies.

Disability was significant among patients with ADCLS and CFS, including inability to work full-time, sleep disturbance, and profound fatigue, and both these groups had significant differences compared with controls. However, ADCLS cases did not differ significantly from CFS cases on any of the measured parameters.

Reference laboratory testing did not confirm positive Lyme serology in any of the ADCLS cases. Furthermore, the groups did not differ in distribution of positive serology for other tick-transmitted pathogens or in cytokine expression.

"Lyme disease diagnosed by alternative laboratory methods is indistinguishable from [CFS] by detailed clinical and laboratory evaluation," the study authors write. "Discordant tests for Lyme disease likely represent false positive results from an alternative lab in our low prevalence setting [in British Columbia]."

Limitations of this study include small sample size with low power to detect small between-group differences, recall bias inherent in case-control studies, possible selection bias, and low generalizability to higher prevalence areas for Lyme disease.

"Those diagnosed with ADCLS deserve comprehensive work-up and care," the study authors conclude. "Many will meet case definitions for CFS and should be included in studies employing metagenomics, transcriptomics and other approaches in the search for a more plausible etiology."

The British Columbia Centre for Disease Control Foundation for Population and Public Health funded this study. The authors have disclosed no relevant financial relationships.

Clin Infect Dis. Published online June 16, 2016. Abstract


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