Number of chlamydia tests and proportion testing positive among all, baseline and repeat tests among young people aged 15 to 24 at their first test (2010)*
| Females | Males | All | ||||
|---|---|---|---|---|---|---|
| GUMCAD | NCSP dataset | GUMCAD | NCSP dataset | GUMCAD | NCSP dataset | |
| Total tests (n) | 311329 | 752993 | 190766 | 482125 | 502095 | 1235058 |
| Baseline tests (n) | 265098 | 672036 | 169658 | 442217 | 434756 | 1114253 |
| Total repeat tests (n) | 46231 | 80897 | 21108 | 39908 | 67339 | 120805 |
| Number of tests per person in 2010 (n, (%)) | ||||||
| 1 | 227631 (87%) | 603815 (90%) | 151851 (90%) | 408192 (92%) | 379482 (87%) | 1012007 (91%) |
| 2 | 30391 (11%) | 57685 (9%) | 15054 (9%) | 29134 (7%) | 45445 (10%) | 86819 (8%) |
| 3 to 5 | 7045 (3%) | 10499 (2%) | 2746 (2%) | 4873 (1%) | 9791 (2%) | 15372 (1%) |
| >5 | 31 (<0.1%) | 37 (<0.1%) | 7 (<0.1%) | 18 (<0.1%) | 38 (<0.1%) | 55 (<0.01%) |
| Maximum | 7 | 7 | 6 | 8 | 7 | 8 |
| Proportion of tests reporting at least one new SP previous 3 months† | ||||||
| Overall (n, (%)) | 201705/438063 (46%) | 121335/216419 (56%) | 323040/654482 (49%) | |||
| Baseline tests (n, (%)) | 176434/393458 (45%) | 110643/200915 (55%) | 287077/594373 (48%) | |||
| Repeat tests (n, (%)) | 25271/44605 (57%) | 10692/15504 (69%) | 35963/60109 (60%) | |||
| Proportion testing positive | ||||||
| Overall (n, (%)) | 34098 (11.0%) | 43404 (5.8%) | 24060 (12.6%) | 20916 (4.3%) | 58158 (11.6%) | 64320 (5.2%) |
| Among baseline tests (n, (%)) | 30112 (11.4%) | 38342 (5.7%) | 21623 (12.8%) | 19271 (4.4%) | 51735 (11.9%) | 57613 (5.2%) |
| Among repeat tests (n, (%)) | 3986 (9.5%) | 5062 (6.3%) | 2437 (11.6%) | 1645 (4.1%) | 6423 (9.5%) | 6707 (5.6%) |
| Proportion repeat tests positive by test result at baseline | ||||||
| Negative baseline test (n, (%)) | 3004/39812 (7.6%) | 3992/71903 (5.6%) | 1728/17584 (9.8%) | 1296/37536 (3.5%) | 4732/57396 (8.2%) | 5288/109439 (4.8%) |
| Positive baseline test (n, (%)) | 982/6419 (15.3%) | 1070/8994 (11.9%) | 709/3524 (20.1%) | 349/2372 (14.7%) | 1691/9943 (17.0%) | 1419/11366 (12.5%) |
| Proportion repeat tests positive by reported sexual behaviour at repeat test | ||||||
| ≥ 1 new SP in past 3 months (n, (%)) | 2113/25271 (8.4%) | 651/10692 (6.1%) | 2764/35963 (7.7%) | |||
| No new SP in past 3 months (n, (%)) | 970/19334 (5.0%) | 171/4812 (3.6%) | 1141/24146 (4.7%) | |||
| Unknown (n, (%)) | 1979/36292 (5.5%) | 825/24404 (3.4%) | 2802/60696 (4.6%) | |||
*Only those with data available for matching in the NCSP dataset were retained; Men who reported ever having sex with a man in GUMCAD were excluded; test records within 6 weeks of a positive or negative test result were considered to be part of the same testing episode and therefore excluded; GUMCAD: Genitourinary Medicine Clinical Activity Database; NCSP: National Chlamydia Screening Programme.
†Proportion reporting at least one new sexual partner in previous 3 months is for those with non-missing data on this variable.
SP, sexual partner.