Guide to the Application of Genotyping to Tuberculosis
Prevention and Control Developing a Tuberculosis Genotyping
Program An important use of genotyping is to detect or confirm
suspected false-positive cultures that are due to cross
contamination, mislabeled specimens, and other errors.
Procedures for dealing with false-positive cultures differ
somewhat, depending on whether the error was suspected before
the genotyping results were known or the error was identified as
a result of the genotyping laboratory report. “Genotyping of TB
isolates is particularly useful in the evaluation of patients
who have only a single culture-positive specimen, a population
for whom up to 40% of the isolates are false-positive. Timely
evaluation of these isolates prevents unwarranted isolation,
treatment and contact investigations. Genotyping is also useful
over the intermediate time period of months to several years in
clarifying the role of recent transmission in high-risk
populations and methods of intervention. Genotyping i