Symptoms suggestive of acute urinary tract infection (UTI) constitute
one of the most common reasons for women to visit clinicians. Although the
clinical encounter typically involves taking a history and performing a physical
examination, the diagnostic accuracy of the clinical assessment for UTI remains
To review the accuracy and precision of history taking and physical
examination for the diagnosis of UTI in women.
We conducted a MEDLINE search for articles published from 1966 through
September 2001 and manually reviewed bibliographies, 3 commonly used clinical
skills textbooks, and contacted experts in the field.
Studies were included if they contained original data on the accuracy
or precision of history or physical examination for diagnosing acute uncomplicated
UTI in women. One author initially screened titles and abstracts found by
our search. Nine of 464 identified studies met inclusion criteria.
Two authors independently abstracted data from the included studies.
Disagreements were resolved by discussion and consensus with a third author.
Four symptoms and 1 sign significantly increased the probability of
UTI: dysuria (summary positive likelihood ratio [LR], 1.5; 95% confidence
interval [CI], 1.2-2.0), frequency (LR, 1.8; 95% CI, 1.1-3.0), hematuria (LR,
2.0; 95% CI, 1.3-2.9), back pain (LR, 1.6; 95% CI, 1.2-2.1), and costovertebral
angle tenderness (LR, 1.7; 95% CI, 1.1-2.5). Four symptoms and 1 sign significantly
decreased the probability of UTI: absence of dysuria (summary negative LR,
0.5; 95% CI, 0.3-0.7), absence of back pain (LR, 0.8; 95% CI, 0.7-0.9), history
of vaginal discharge (LR, 0.3; 95% CI, 0.1-0.9), history of vaginal irritation
(LR, 0.2; 95% CI, 0.1-0.9), and vaginal discharge on examination (LR, 0.7;
95% CI, 0.5-0.9). Of all individual diagnostic signs and symptoms, the 2 most
powerful were history of vaginal discharge and history of vaginal irritation,
which significantly decreased the likelihood of UTI when present (LRs, 0.3
and 0.2, respectively). One study examined combinations of symptoms, and the
resulting LRs were more powerful (24.6 for the combination of dysuria and
frequency but no vaginal discharge or irritation). One study of patients with
recurrent UTI found that self-diagnosis significantly increased the probability
of UTI (LR, 4.0).
In women who present with 1 or more symptoms of UTI, the probability
of infection is approximately 50%. Specific combinations of symptoms (eg,
dysuria and frequency without vaginal discharge or irritation) raise the probability
of UTI to more than 90%, effectively ruling in the diagnosis based on history
alone. In contrast, history taking, physical examination, and dipstick urinalysis
are not able to reliably lower the posttest probability of disease to a level
where a UTI can be ruled out when a patient presents with 1 or more symptoms.