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Three Part Question

In [asymptomatic individuals] is [urine dipstick testing for glucose] sensitive enough to be used as [a screening tool for diabetes mellitus ]

Clinical Scenario

An asymptomatic conscript walks into the Medical Centre and provides a urine sample for testing for glycosuria as part of a screening procedure for Diabetes Mellitus. How useful is a urine dipstick in screening for the condition.

Search Strategy

Ovid MEDLINE 1966 to October Week 4 2005
Embase 1980 to 2005 week 47
The Cochrane Library Issue 4 2005
Medline:[{ exp diabetes mellitus/OR diabetes mellitus.mp OR diabet$.mp OR IDDM.mp OR NIDDM.mp} AND { exp urine/OR urin$.mp} AND {exp reagent strips/OR exp glycosuria/OR exp "indicators and reagents/" OR stix.mp OR glucostix.mp OR stick.mp} AND { screen$.mp OR diagnos$.mp}] LIMIT to human and English language.
Embase:[exp diabetes mellitus/OR diabetes mellitus.mp. OR diabet$.mp. OR IDDM.mp. OR NIDDM.mp.] AND [exp urine/OR urin$.mp.] AND [exp test strip/OR exp glucosuria/OR stix.mp. OR glucostix.mp. OR stick.mp.] AND [screen$.mp. OR diagnos$] LIMIT to human and English Language
Cochrane: Diabetes mellitus [MeSH] AND (Reagent strips [MeSH] OR reagent kits, diagnostic [MeSH] 20 hits

Search Outcome

178 papers found, of which 173 either did not answer the three part question or were review articles with no original data. The remaining five are shown below.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
West KM & Kalbfleisch JM 1971 USA	4262 subjects (including 50 known diabetics) in 10 countries	Prospective diagnostic study	+ve urine clinistix test. DM diagnosed by blood glucose 2h after glucose load	Sensitivity 35.3% (fasting) 38.9% (2-4h after food) 67.0% (after 1g/kg oral glucose) Specificity 99.7% (fasting) 97.6% (2-4h after food) 94.4% (after oral glucose)	Diagnostic blood glucose lower than current WHO criteria False negative rate not extrapolated to whole population in sensitivity calculation Statistical significance/95% C.I. not assessed Subject selection not discussed
Davidson JK et al, 1978, USA	1952 patients aged 16-76 not known to have DM presenting to medical clinic	Prospective diagnostic study	+ve urine clinitest. DM diagnosed in 20 of 25 +ve patients by fasting glucose or OGTT. 25 normoglucosuric patients underwent OGTT	Sensitivity 74% Specificity 86% (p<0.05)	Diagnostic blood glucose lower than current WHO criteria False negative rate not extrapolated to whole population in sensitivity calculation
Anderson DKG et al, 1992, Sweden	3201 patients aged 35-79 not known to have DM presenting to GP	Prospective diagnostic study	+ve redia urine test. DM diagnosed by fasting glucose or OGTT. All patients 3 year follow up	Sensitivity 18.1% Specificity 99.1%	3 year follow up may overestimate false negatives Statistical significance/95% C.I. not assessed
Davies MJ et al, 1993, UK	442 consecutive patients aged 40-65 not known to be diabetic in larger postal study	Prospective diagnostic study	+ve urine test. All had OGTT	Sensitivity 44% Specificity 98%	Statistical significance/95% C.I. not assessed for sensitivity Selection criteria not clear
Friderichsen B & Maunsbach M, 1997, Denmark	1530 patients aged 45-76 responding to postal survey of 3041.	Prospective diagnostic study	+ve urine glukotest R. DM diagnosed by fasting blood glucose	Sensitivity 20.80% (95% C.I. 8.14-52.81%) Specificity 99.14% (95% 98.54-99.59%)

Comment(s)

If the sensitivity of the first two studies are recalculated, extrapolating the documented prevalence of diabetes in each group to the patients who were considered true negative with no further tests, then the resultant sensitivities are 34.1% and 50.4% respectively. This is a reflection of the chances of finding glycosuria in a diabetic rather than the quality of urine dipsticks. Specificities are high, however low sensitivities preclude their use as a screening tool.

Clinical Bottom Line

Urine dipsticks are of insufficient sensitivity to be used as a screening tool in an asymptomatic population.

References

1. West KM, Kalbfleisch JM. Sensitivity and specificity of five screening tests for diabetes in ten countries. Diabetes 1971;20(5):289-96.
2. Davidson JK, Reuben D, Sternberg JC et al. Diabetes screening using a quantitative urine glucose method. Diabetes 1978;27(8):810-6.
3. Andersson DK, Lundblad E, Svardsudd K. A model for early diagnosis of type 2 diabetes mellitus in primary health care. Diabetic Medicine 1993;10(2):167-73.
4. Davies MJ, Williams DR, Metcalfe J et al. Community screening for non-insulin-dependent diabetes mellitus: self-testing for post-prandial glycosuria. Quarterly Journal of Medicine 1993;86(10):677-84.
5. Friderichsen B, Maunsbach M. Glycosuric tests should not be employed in population screenings for NIDDM. J Public Health Med 1997;19(1):55-60.