Molecular methods in the laboratory diagnosis of sexually transmitted infections

Sexually transmitted infections (STIs) are a public health problem, and their prevalence is rising even in developed nations, in the era of HIV/AIDS. While the consequences of STIs can be serious, the good news is that many of these complications are preventable if appropriate screening is done in high-risk individuals, when infection is strongly suspected. The diagnostic tests for STIs serve many purposes. Apart from aiding in the diagnosis of typical cases, they help diagnose atypical cases, asymptomatic infections and also multiple infections. But, the test methods used must fulfill the criteria of accuracy, affordability, accessibility, efficiency, sensitivity, specificity and ease of handling. The results must be rapid, cost-effective and reliable. Most importantly, they have to be less dependent on collection techniques. The existing diagnostic methods for STIs are fraught with several challenges, including delay in results, lack of sensitivity and specificity. With the rise of the machines in diagnostic microbiology, molecular methods offer increased sensitivity, specificity and speed. They are especially useful for microorganisms that cannot be, or are difficult to cultivate. With the newer diagnostic technologies, we are on the verge of a major change in the approach to STI control. When diagnostic methods are faster and results more accurate, they are bound to improve patient care. As automation and standardization increase and human error decreases, more laboratories will adopt molecular testing methods. An overview of these methods is given here, including a note on the point-of-care tests and their usefulness in the era of rapid diagnostic tests.