Urinary Tract Infection: Likelihood Ratios

Introduction: An uncomplicated, or lower, UTI is also known as cystitis. The principal symptoms are dysuria, frequency, urgency; hematuria can also be present.

Non-diagnostic historical findings (from Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379) include:

history of backache, fever, feeling unwell, abdominal pain, prior duration, daytime or night-time frequency (number of times), renal angle tenderness, lower abdominal tenderness, previous history of UTI.

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Differential Diagnoses include: Appendicitis, Pyelonephritis

Prevalence

Population / Calculator	Prevalence	Comments / Study / Link
Women with suspected UTI	62%	Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
	50%
	45%
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The likelihood ratios of findings for Urinary Tract Infection are listed below. See the left navigation bar to change the display.

Good Positive and Negative Likelihood Ratios

Finding	+LR	-LR	Comments, Study
Self-Diagnosis	4	0	Study: JAMA. 2002;287:2701-2710. http://jama.ama-assn.org/cgi/content/full/287/20/2701
Urine Culture	6.3	0.1	>10^2 CFU/ml of E coli. Population: symptomatic women. Study: N Engl J Med 1982 Aug 19;307(8):463-8. PMID 7099208
Pyuria	3.3	0.1	i.e. microscopic leukocytes Study: N Engl J Med. 2003 Jul 17;349(3):259-66. PMID 12867610
Dipstick Leukocyte Esterase or Nitrite	4.2	0.3	Study: N Engl J Med. 2003 Jul 17;349(3):259-66. PMID 12867610
Dipstick Nitrite or Dipstick Blood and Leukocyte Esterase	2.6	0.3	Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
Bacteriuria	4.7	0.4	i.e. microscopically visible bacteria in urine (sensitivity depends a lot on the cutoff number of bacteria) Study: N Engl J Med. 2003 Jul 17;349(3):259-66. PMID 12867610

Good Negative Likelihood Ratio

Dipstick Leukocyte Esterase

1.8

0.3

Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379

Dipstick Blood

1.6

0.5

Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379

Good Positive Likelihood Ratio

Finding	+LR	-LR	Comments, Study
Dipstick Nitrite	3.1	0.8	Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
Urine Malodor	2.4	0.8	Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
Cloudy Urine	2.2	0.7	Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379

Poorly Diagnostic Findings

Finding	+LR	-LR	Comments, Study
Hematuria	1.9	0.9	moderately severe Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
Costovertebral Angle Tenderness	1.8	0.9	Study: JAMA. 2002;287:2701-2710. http://jama.ama-assn.org/cgi/content/full/287/20/2701
Dipstick Protein	1.5	0.8	Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
Nocturia	1.5	0.7	moderately severe (population is women with suspected UTI) Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
Urinary Urgency	1.2	0.8	moderately severe Study: Br J Gen Pract. 2006 Aug;56(529):606-12. PMID 16882379
Flank Pain	1.1	0.9	Study: JAMA. 2002;287:2701-2710. http://jama.ama-assn.org/cgi/content/full/287/20/2701