EBQ:Hematuria in Renal Colic

incomplete Journal Club Article

Luchs J. et al.. "Utility of hematuria testing in patients with suspected renal colic: correlation with unenhanced helical CT results". Urology. 2002. 59(6):839-42.
PubMed

Clinical Question

How accurate is urinalysis for detecting ureteral stones?

Conclusion

The presence or absence of blood on urinalysis cannot be used to reliably determine which patients have ureteral stones.

Major Points

Urinalysis compared to noncontrast CT (gold standard):
Sensitivity 84%
Specificity 48%

Study Design

Retrospective chart review of 950 patients who had a formal microscopic urinalysis within 24 hours of undergoing a non-contrast helical CT.

Population

• Patients presenting to single institution with suspected renal colic who underwent both unenhanced helical computed tomography (CT) and microscopic urinalysis testing within a 24-hour period

Interventions

Workup and treatment according to treating physician (retrospective review).

Outcomes

Primary Outcome

• The sensitivity of blood on the urinalysis for CT-confirmed renal colic was 84%
• The specificity of blood on the urinalysis for CT-confirmed renal colic was 48%
• The positive predictive value of blood on the urinalysis for CT-confirmed renal colic was 72%
• The negative predictive value of blood on the urinalysis for CT-confirmed renal colic was 65%

Secondary Outcomes

• 62% of patients had CT-evidence of stone or recently passed stone
• 31% of patients had completely negative CT scans
• 7% of patients had significant alternative diagnoses

Subgroup analysis

Using higher threshold for positive urinalysis (10 or more RBC/mL urine):

• The sensitivity of blood on the urinalysis for CT-confirmed renal colic was 81%
• The specificity of blood on the urinalysis for CT-confirmed renal colic was 51%
• The positive predictive value of blood on the urinalysis for CT-confirmed renal colic was 73%
• The negative predictive value of blood on the urinalysis for CT-confirmed renal colic was 62%

Funding

Not disclosed, and authors do not report any conflicts of interest

See Also

• Urolithiasis