Table 2.
Diagnostic performances of UWCC, parallel UWCC/GSUS and stratified diagnosis for the prediction of Chlamydia trachomatis or Mycoplasma genitalium infection using validation samples
| Diagnostic performance comparison of UWCC versus UWCC and GSUS performed in parallel using validation samples (n=228) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| UWCC* sensitivity | Parallel UWCC* and GSUS† sensitivity | p Value‡ | UWCC* specificity | Parallel UWCC* and GSUS† specificity | p Value‡ | UWCC* PPV§ | Parallel UWCC and GSUS PPV§ | UWCC* NPV¶ | Parallel UWCC and GSUS NPV¶ | |
| C. trachomatis | 71.4% (42 to 90.4) |
78.6% (48.8 to 94.3) |
0.5 | N/A | N/A | 29.4% (15.7 to 47.6) |
26.8% (14.8 to 43.2) |
97.9% (94.4 to 99.3) |
98.3% (95 to 99.5) |
|
| M. genitalium | 66.6% (35.4 to 88.7) |
66.60% (35.4 to 88.7) |
0.25 | N/A | N/A | 23.5% (11.3 to 41.5) |
19.5% (93 to 35.3) |
97.9% (94.4 to 99.3) |
97.9% (94.3 to 99.3) |
|
|
C. trachomatis or M. genitalium |
69.2% (48.1 to 84.9) |
73% (51.9 to 87.6) |
0.031 | 92% (87.2 to 95.2) |
89.1% (83.7 to 92.8) |
0.03 | 53% (35.3 to 69.8) |
46.3% (30.9 to 60.3) |
95.8% (91.7 to 98) |
96.2% (92.1 to 98.3) |
| Diagnostic performance comparison of UWCC versus stratified diagnosis using validation samples of asymptomatic patients only (n=176) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| UWCC* sensitivity | Stratified diagnosis** sensitivity | p Value‡ | UWCC* specificity | Stratified diagnosis** specificity | p Value‡ | UWCC* PPV§ | Stratified diagnosis PPV§ | UWCC* NPV¶ | Stratified approach NPV¶ | |
| C. trachomatis | 100% (40.3% to 100%) |
60% (17% to 92.7%) |
0.5 | N/A | N/A | 19.2% (7.3% to 39.9%) |
30% (8% to 64.6%) |
100% (96.8% to 100%) |
98.8% (95.3% to 99.8%) |
|
| M. genitalium | 50% (17.4% to 82.6%) |
12.5% (0.6% to 53.3%) |
0.25 | N/A | N/A | 15.4% (5% to 35.7%) |
10% (0.5% to 45.9%) |
97.3% (92.9% to 99.1%) |
95.8% (91.1% to 98.1%) |
|
|
C. trachomatis or M. genitalium |
71.4% (42% to 90.4%) |
28.6% (9.6% to 58%) |
0.031 | 90.1% (84.2% to 94%) |
96.3% (91.8% to 98.5%) |
<0.01 | 38.5% (20.9% to 59.3%) |
40% (13.7% to 72.6%) |
97.3% (92.9% to 99.1%) |
93.8% (88.9% to 96.9%) |
*UWCC were defined as positive if the patient’s urine contained >29 White blood cell per µL.
†GSUS testing containing >5 PMN per high power fields (HPFs) over 5 HPFs was examined.
‡p Values represent the results of statistical comparisons of either sensitivity or specificity between the two test methodologies. These were generated using McNemar’s test for paired binary data with the results of C. trachomatis NAAT testing upon BD Viper System or real-time PCR for M. genitalium as the reference standards.
§Positive predictive value.
¶Negative predictive value.
**Positive stratified diagnosis is defined as patients treated for urethritis due to suggestive clinical history.
GSUS, Gram-stained urethral smear; NAAT, nucleic acid amplification testing; UWCC, urinary white cell counts.