Interlaboratory agreement study of a double set of PCR plasmid primers for detection of Chlamydia trachomatis in a variety of genitourinary specimens.

We conducted a tricenter interlaboratory agreement study to assess the agreement of PCR results obtained for detection of Chlamydia trachomatis in genitourinary specimens. A total of 120 specimens (49 positive and 71 negative), including 20 first-void urine samples, 50 endocervical and 50 urethral swabs (40 males), were coded and sent from a reference laboratory (laboratory A) to two other laboratories. Laboratories B and C were provided with a standardized protocol and reagent package including two sets of plasmid PCR primers (KL1-KL2 and T1-T2) and were asked to test each specimen with the first set of primers (KL1-KL2) and to confirm positives with the second set of primers (T1-T2).