What is the reference method for detection of Chlamydia trachomatis in cases of sexually transmitted disease?

• A. DNA-amplification techniques
• B. Nonculture ELISA methods
• C. Tissue culture
• D. Culture on modified Thayer-Martin agar

Answer: (A)

Detecting Chlamydia trachomatis most reliably in clinical samples is done with nucleic acid amplification tests. These assays amplify and detect specific DNA sequences from the organism, which gives very high sensitivity and specificity. Because they don’t require live bacteria, they can be used on noninvasive samples like urine or vaginal/cervical swabs and yield rapid results, making them ideal for routine screening and diagnosis in STD clinics.

Traditionally, culture in living cells was used, but it is technically demanding, slower, and less practical in many settings, which is why it’s not the preferred reference method today. Other methods that rely on protein detection (like ELISA) or culture on media such as modified Thayer-Martin agar are not as reliable for Chlamydia trachomatis as DNA amplification techniques.