Background
Methods
Literature search
Quality and applicability of studies
Potential sources of heterogeneity
Meta-analysis
Results
Literature search
Quality and applicability of studies
Meta-analysis
Nitrites (n = 58)
Study characteristic | N | Sensitivity(95%CI) | Specificity(95%CI) | DOR(95%CI) |
---|---|---|---|---|
BLINDING# | ||||
not | 12 | 0.50 (0.43–0.59) | 0.89 (0.75–1.00) | 44 (19 – 139) |
dipstick | 25 | 0.46 (0.38–0.56) | 0.91 (0.85–0.96) | 28 (27 – 30) |
both | 8 | 0.55 (0.36–0.85) | 0.96 (0.94–0.98) | 99 (41 – 239) |
DATA COLLECTION# | ||||
prospective | 42 | 0.48 (0.42–0.55) | 0.91 (0.86–0.96) | 34 (21 – 57) |
retrospective | 1 | 0.37 (0.28–0.46) | 1.00 (0.99–1.00) | 701 (43 – 11565) |
CUT-OFF CRITERION STANDARD* | ||||
<1000 mcu/ml | 5 | 0.62 (0.56–0.69) | 0.92 (0.84–1.00) | 32 (9 – 112) |
10.000–50.000 | 9 | 0.37 (0.28–0.48) | 0.93 (0.88–0.98) | 18 (6 – 51) |
≥100.000 | 34 | 0.48 (0.40–0.57) | 0.93 (0.87–0.98) | 50 (29 – 84) |
POPULATION# | ||||
general | 15 | 0.50 (0.44–0.58) | 0.82 (0.71–0.95) | 11 (6 – 21) |
children | 10 | 0.50 (0.42–0.60) | 0.92 (0.87–0.98) | 34 (12 – 97) |
pregnant women | 10 | 0.46 (0.38–0.56) | 0.98 (0.79–1.00) | 165 (73 – 372) |
elderly | 3 | 0.71 (0.50–1.00) | 0.96 (0.91–1.00) | 108 (10 – 1165) |
urology | 3 | 0.59 (0.53–0.66) | 0.97 (0.94–1.00) | 64 (19 – 216) |
surgery | 3 | 0.54 (0.39–0.74) | 0.96 (0.93–0.99) | 34 (25 – 47) |
SETTING# | ||||
family physician | 6 | 0.53 (0.44–0.65) | 0.88 (0.81–0.96) | 12 (7 – 21) |
outpatient | 17 | 0.45 (0.37–0.56) | 0.96 (0.92–0.99) | 87 (38 – 198) |
emergency | 4 | 0.56 (0.40–0.81) | 0.94 (0.90–0.98) | 34 (10 – 112) |
inpatient | 16 | 0.58 (0.51–0.67) | 0.85 (0.74–0.98) | 23 (10 – 54) |
LEVEL OF CARE | ||||
community | 2 | 0.18 (0.04–0.76) | 0.99 (0.98–1.00) | 78 (34 – 181) |
primary | 12 | 0.49 (0.38–0.62) | 0.85 (0.73–1.00) | 22 (9 – 53) |
secondary | 11 | 0.51 (0.40–0.66) | 0.89 (0.78–1.00) | 61 (15 – 247) |
tertiary | 21 | 0.53 (0.46–0.60) | 0.94 (0.93–0.96) | 39 (22 – 69) |
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blinding: only in double-blind studies were sensitivity and specificity found to be highly negatively correlated (ρ = -0.647) with a homogeneous ln(DOR). In unblinded studies the ln(DOR) was associated with the cut-off point for a positive result of the dipstick, and in single blind studies it was associated with both the cut-off point and the general population;
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patient populations: sensitivity and specificity were highly negatively correlated in studies involving general populations (ρ = -0.539), pregnant women (ρ = -0.559) and surgery patients (ρ = -1.00), resulting in a homogeneous ln(DOR). In multiple meta-regression, the ln(DOR) for studies in general populations was associated with the cut-off point of the dipstick, supra-pubic urine-collection and automatic or visual reading. For studies in pregnant women it was associated with the presence of clinical information, and for studies in children it was associated with the cut-off point of the dipstick only;
-
care setting: strong negative correlations existed between sensitivity and specificity in family practices (ρ = -0.714) and emergency departments (ρ = -0.400) with a homogeneous ln(DOR) in both sub-groups. In multivariate meta-regression analysis, the ln(DOR) was associated in family practices with the pre-test probability; in outpatient departments it was associated with the cut-off point of the dipstick, and in inpatient departments with the cut-off point, pre-test probability, automatic or visual reading, and the presence of clinical information.
Post-test probability (predictive value) | |||||
---|---|---|---|---|---|
Pre-test Probability (prevalence) | Nitrites | Leucocyte-esterase | One or both positive | Both positive | |
Population | |||||
General population | .15 | ||||
- Test + | .33 | .27 | .31 | .89 | |
- Test - | .90 | .91 | .94 | .91 | |
Children | .20 | ||||
- Test + | .61 | .34 | .58 | .66 | |
- Test - | .88 | .88 | .95 | .87 | |
Pregnant women | .06 | ||||
- Test + | .55 | .10 | .58 | (.99) | |
- Test - | .97 | .97 | .95 | (.96) | |
Elderly | .30 | ||||
- Test + | .88 | .47 | .55 | (.90) | |
- Test - | .89 | .81 | .90 | (.86) | |
Surgery | .15 | ||||
- Test + | .70 | .27 | .51 | (.38) | |
- Test - | .92 | .91 | .97 | (.94) | |
Urology | .15 | ||||
- Test + | .78 | .68 | .54 | ||
- Test - | .93 | .97 | .98 | ||
Setting | |||||
Family physician | .55 | ||||
- Test + | .84 | .62 | .76 | ||
- Test - | .61 | .69 | .84 | ||
Outpatient | .10 | ||||
- Test + | .56 | .22 | .32 | ||
- Test - | .94 | .94 | .97 | ||
Inpatient | .15 | ||||
- Test + | .41 | .38 | .38 | ||
- Test - | .92 | .93 | .95 | ||
Emergency | .15 | ||||
- Test + | .62 | .41 | .41 | ||
- Test - | .92 | .92 | .98 |
Leukocyte-esterase (n = 42)
Study characteristic | N | Sensitivity(95%CI) | Specificity(95%CI) | DOR(95%CI) |
---|---|---|---|---|
POPULATION# | ||||
non-urological | 33 | 0.62 (0.54–0.71) | 0.70 (0.60–0.81) | 9 (6 – 12) |
urological | 2 | 0.86 (0.68–1.00) | 0.93 (0.81–1.00) | 276 (2 – 41974) |
NON-UROLOGICAL STUDIES (N = 33) | ||||
DISEASE# | ||||
bacteriuria | 8 | 0.56 (0.38–0.82) | 0.61 (0.41–0.90) | 5 (5 – 8) |
UTI | 25 | 0.64 (0.56–0.74) | 0.73 (0.63–0.85) | 11 (6 – 19) |
SETTING | ||||
family physician | 6 | 0.87 (0.83–0.92) | 0.36 (0.21–0.64) | 5 (2 – 28) |
outpatient | 12 | 0.50 (0.35–0.68) | 0.80 (0.72–0.88) | 8 (5 – 12) |
emergency | 3 | 0.56 90.41–0.75) | 0.86 (0.74–0.99) | 14 (2 – 119) |
inpatient | 11 | 0.66 (0.60–0.73) | 0.81 (0.74–0.88) | 11 (8 – 16) |
LEVEL OF CARE | ||||
community | 1 | 0.63 (0.08–1.00) | 0.85 (0.82–0.88) | 9 (1 – 72) |
primary care | 10 | 0.76 (0.60–0.98) | 0.46 (0.32–0.68) | 6 (3 – 11) |
secondary care | 8 | 0.48 (0.33–0.71) | 0.83 (0.73–0.93) | 8 (4 – 14) |
tertiary care | 14 | 0.62 (0.55–0.70) | 0.84 (0.80–0.89) | 13 (8 – 20) |
READER OF TEST | ||||
family physician | 2 | 0.86 (0.71–1.00) | 0.17 (0.04–0.62) | 2 (0.3 – 10) |
nurse | 7 | 0.67 (0.58–0.79) | 0.65 (0.37–1.00) | 7 (4 – 10) |
clinician | 2 | 0.34 (0.18–0.64) | 0.90 (0.68–1.00) | 7 (0.5 – 87) |
lab worker | 17 | 0.59 (0.47–0.73) | 0.81 (0.76–0.87) | 11 (7 – 18) |
Nitrite and leucocyte-esterase: one or both positive (n = 39)
Study characteristic | N | Sensitivity(95%CI) | Specificity(95%CI) | DOR(95%CI) |
---|---|---|---|---|
Nitrites and Leucocyte-esterase: one or both positive (N = 35)
| ||||
CUT-OFF CRITERION STANDARD#* | ||||
≥103 mcu/ml | 2 | 0.45 (0.00–1.00) | 0.62 (0.00–1.00) | 4 (0.8 – 15) |
≥104 mcu/ml | 11 | 0.67 (0.53–0.87) | 0.78 (0.73–0.84) | 12 (7 – 23) |
≥105 mcu/ml | 27 | 0.80 (0.76–0.86) | 0.80 (0.76–0.84) | 25 (17 – 38) |
POPULATION# | ||||
general population | 12 | 0.75 (0.61–0.93) | 0.70 (0.63–0.78) | 12 (6 – 22) |
children | 9 | 0.83 (0.78–0.89) | 0.85 (0.79–0.91) | 46 (23 – 95) |
pregnant women | 5 | 0.68 (0.58–0.78) | 0.87 (0.81–0.92) | 17 (10 – 30) |
elderly | 4 | 0.82 (0.74–0.92) | 0.71 (0.55–0.71) | 16 (8 – 34) |
surgery | 2 | 0.86 (0.84–0.88) | 0.86 (0.84–0.87) | 43 (22 – 85) |
urology | 3 | 0.88 (0.76–1.00) | 0.87 (0.83–0.91) | 52 (48 – 56) |
SETTING | ||||
family physician | 2 | 0.90 (0.89–0.92) | 0.65 (0.61–0.69) | 18 (13 – 25) |
outpatient | 13 | 0.75 (0.69–0.82) | 0.82 (0.77–0.87) | 18 (12 – 27) |
emergency | 1 | 0.92 (0.86–0.98) | 0.83 (0.81–0.85) | 54 (25 – 117) |
inpatient | 19 | 0.79 (0.69–0.91) | 0.77 (0.70–0.84) | 25 (14 – 46) |
CLINICAL INFORMATION# | ||||
Absent | 11 | 0.73 (0.58–0.91) | 0.75 (0.78–0.82) | 13 (7 – 25) |
Present | 24 | 0.81 (0.77–0.87) | 0.79 (0.73–0.85) | 28 (18 – 44) |
BRAND DIPSTICK# | ||||
Multistix | 26 | 0.79 (0.71–0.87) | 0.77 (0.72–0.82) | 21 (13 – 33) |
Chemstrips | 6 | 0.73 (0.61–0.87) | 0.86 (0.81–0.91) | 24 (12 – 50) |
Combur | 1 | 0.78 (0.69–0.88) | 0.97 (0.96–0.97) | 102 (77 – 136) |
NITRITES AND LEUCOCYTE-ESTERASE: BOTH POSITIVE (N = 14)
| ||||
CUT-OFF CRITERION STANDARD#* | ||||
≥103 mcu/ml | 1 | 0.45 (0.29–0.61) | 0.62 (0.50–0.74) | 1 (0.6 – 3) |
≥104 mcu/ml | 3 | 0.31 (0.16–0.60) | 0.96 (0.93–0.99) | 14 (5 – 41) |
≥105 mcu/ml | 12 | 0.44 (0.32–0.60) | 0.96 (0.92–1.00) | 75 (31 – 185) |
POPULATION# | ||||
general population | 3 | 0.45 (0.27–0.75) | 0.99 (0.98–1.00) | 15 (7 – 32) |
children | 6 | 0.46 (0.30–0.71) | 0.94 (0.94–0.94) | 151 (51 – 448) |
pregnant women | 1 | 0.17 (0.02–0.32) | 1.00 (0.99–1.00) | 429 (22 – 8210) |
elderly | 1 | 0.63 (0.41–0.85) | 0.98 (0.92–1.00) | 89 (14 – 70) |
surgery | 1 | 0.72 (0.64–0.80) | 0.77 (0.74–0.80) | 9 (6 – 13) |
spinal | 1 | 0.47 (0.37–0.57) | 0.99 (0.97–1.00) | 72 (13 – 394) |