title: Reasons for false-positive lipoarabinomannan ELISA results in a Tanzanian population.
abstract: Lipoarabinomannan (LAM), a cell wall component of mycobacteria, can be detected in the urine of tuberculosis (TB) patients. Advantages of this diagnostic include the ease of sample collection and test methods. However, as with most new TB diagnostics, LAM tests have been evaluated in well-controlled laboratory settings and subsequently need assessment under real working conditions. Our experience showed that the diagnosis of TB using the detection of LAM in urine under field conditions is prone to false-positive results due to contamination. Dust and soil, but also stool, seemed to lead to increased OD values and thus false-positive results of the enzyme-linked immunosorbent assay (ELISA) for LAM; however, contamination with blood, as well as bacterial or fungal organisms, had no influence. The collection of urine for the detection of LAM should therefore follow strict collection criteria in order to avoid contamination.
authors.affiliation: From the Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich , Munich , Germany.
authors.forename: Inge
authors.initials: I
authors.lastname: Kroidl
authors.forename: Petra
authors.initials: P
authors.lastname: Clowes
authors.forename: Joshua
authors.initials: J
authors.lastname: Mwakyelu
authors.forename: Leonard
authors.initials: L
authors.lastname: Maboko
authors.forename: Abubakary
authors.initials: A
authors.lastname: Kiangi
authors.forename: Andrea
authors.initials: A
authors.lastname: Rachow
authors.forename: Klaus
authors.initials: K
authors.lastname: Reither
authors.forename: Jutta
authors.initials: J
authors.lastname: Jung
authors.forename: Anthony
authors.initials: A
authors.lastname: Nsojo
authors.forename: Elmar
authors.initials: E
authors.lastname: Saathoff
authors.forename: Michael
authors.initials: M
authors.lastname: Hoelscher
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008070:Lipopolysaccharides / Q000652:urine*; D008297:Male; D008875:Middle Aged; D013048:Specimen Handling / Q000379:methods*; D013636:Tanzania; D014376:Tuberculosis / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D008070:Lipopolysaccharides; C050016:lipoarabinomannan