URINE
DIPSTICK AS A SCREENING TEST FOR SERUM CREATININE ELEVATION IN EMERGENCY
DEPARTMENT PATIENTS WITH SEVERE HYPERTENSION.
Karras
DJ, et al. Acad Emerg Med 2002 Jan;9(1):27-34.
OBJECTIVE:
Patients presenting to the emergency department (ED) with severe hypertension
require assessment for acute end-organ damage. Serum creatinine (SCr)
measurement is routinely recommended to detect renal dysfunction. The authors
assessed the utility of the urine dipstick test in screening for acute SCr
elevation in this population.
METHODS:
The authors performed a prospective study of adult ED patients with diastolic
blood pressures > or = 115 mm Hg that persisted for > or = 30 minutes or
necessitated emergent treatment. Excluded were menstruating and pregnant women
and patients with urinary infection, trauma, or dialysis dependence. Patients
reporting a history of renal disease were excluded if the SCr was abnormal and
no baseline value was available. Each subject had an SCr and urine dipstick
test. The authors examined the performance of the dipstick in identifying an
elevated SCr, defined as SCr > 1.2 mg/dL or > 25% above baseline.
RESULTS:
Of 143 patients, 42 had SCr > 1.2 mg/dL. Eighteen reported prior renal
disease but had an SCr that was normal or < or = 25% above baseline. The
remaining 24 subjects comprised the elevated SCr group. The presence of either
proteinuria or hematuria on dipstick identified these patients with 100%
sensitivity and 29.7% specificity. Specificity rose to 42.4% without loss of
sensitivity when an abnormal dipstick was defined as hematuria or > or = 1+
proteinuria.
CONCLUSIONS:
The urine dipstick may be an effective screening test for SCr elevation in
patients with severe hypertension. A restrictive definition of an abnormal
dipstick would identify all patients with elevated SCr and substantially reduce
the number of SCr assays necessary.