Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1416 page)

SEXUALLY TRANSMITTED INFECTIONS, MOLECULAR DIAGNOSIS (
CHLAMYDIA TRACHOMATIS
,
NEISSERIA GONORRHOEAE
,
TRICHOMONAS VAGINALIS
)

   Definition

   Amplified nucleic acid techniques (NAATs) are the most sensitive tests for detection of common sexually transmitted infections (STI),
C
.
trachomati
s,
N
.
gonorrhoeae
, and
T
.
vaginalis
, in urine and urogenital specimens. Culture techniques for detection of these pathogens require specialized culture, long turnaround time, and transport conditions that are often not realized in clinical practice.

   Special Collection and Transport Instructions

   Commercially available NAATs may be validated for use with urine and urogenital specimens (including Pap thin-prep solutions). They are not validated for use with other types of specimens.

   NAATs should not be used for the sole testing technique in the evaluation of rape or child abuse.

   Specimens must be collected according to the manufacturer’s instructions, including specimen type and materials. Use collection kits provided by the manufacturer for swab and urine specimen; transfer vials may be provided for thin-prep specimens. Ensure that vials for liquid specimens are filled with the appropriate volume.

   Care must be taken to prevent cross-contamination of specimens, for example, at the area used for transfer of urine into a transfer vial.

   Transport to the laboratory at refrigerator or room temperature.

   Use

   Specimens may be submitted for evaluation of sexually active adult patients with symptoms consistent with STDs. Commercially available NAATs for detection of
C
.
trachomatis
,
N
.
gonorrhoeae
, and
T
.
vaginalis
have very high sensitivity and specificity (>95%).

   
Turnaround time:
24–72 hours.

   Interpretation