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Sensitivity of US by ED Physicians for demonstrating ureteric obstruction

Three Part Question

[in adults presenting to A&E with loin pain] [what is the sensitivity and specificity of ultrasonography by emergency physicians compared to radiologists] for [demonstrating ureteric obstruction]

Clinical Scenario

A 35 year old male presents to the emergency department with loin pain. The consultant emergency physician performs an ultrasound (US) scan and confirms diagnosis of renal calculi. The FY1 wonders if emergency physicians are competent at performing US scans.

Search Strategy

Ovid MEDLINE 1946 to June week 3 2012
Embase 1974 to 2012 July
Cochrane Database of Systematic Reviews 2005 to June 2012
[exp Ultrasonography, Interventional/ or exp Ultrasonography, Doppler/ or exp Ultrasonography, Doppler, Pulsed/ or exp Ultrasonography/ or exp Ultrasonography, Doppler, Duplex/ or exp Ultrasonography, Doppler, Color/] OR [ultraso$.mp.] OR [] AND [exp Ureteral Obstruction/] OR [ureteric] OR [obstructive] AND [exp Emergency Service, Hospital/ or exp Emergency Medicine/ or exp Emergency Medical Services/] OR [emergency]

Search Outcome

12 papers found Medline
5 papers found EMBase
3 papers found Pubmed
5 relevant papers found.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Gaspari R and Horst K
Patients presenting to ED with loin pain suspicious of renal colicProspective diagnostic study: 104 patients enrolled and received both US and CT. 58 diagnosed with renal calculi.Sensitivity and specificity of US at diagnosing hydronephrosis by emergency physicians46 of 53 stones detected by US. Sensitivity 86.8% specificity 82.4% PPV 83.6% NPV 85.7%Convenience sample. 31 patients lost to follow up. No patients between 12pm and 8am included
Jang T, Casey J, Dyne P et al
Patients presenting to ED with abdo or loin pain suggestive of obstructive uropathyProspective Cohort study: 393 patients enrolled and received both US and CT, 157 diagnosed with obstructing calculi. Sensitivity and specificity of US at diagnosing obstructive uropathy, stratified by number of times each physician had performed USOverall sensitivity 82% specificity 88%. After physicians had performed 30 exams: sensitivity 95%; specificity 92%; PPV 86%; NPV 97% Convenience sample. 31 patients missed – possible selection bias. Physicians performing US not blinded to patient history.
Kartal M, Eray O, Erdogru T et al.
Consecutive patients presenting to ED with unilateral loin pain Prospective diagnostic study: 227 patients enrolled, 176 diagnosed with renal stones on either IVU, CT or passage of stones.Sensitivity and specificity of US detection of pelvicalyceal dilatation by ED physicians. Sensitivity 81%. Specificity 37%.US operators not blinded. Stones may have been missed by patients during urination or on IVU.
Moak J, Lyons M, Lindsell C
Patients awaiting CT scan for presumed renal colic. Prospective diagnostic study: 107 patients enrolled, all received US and CT. Primary: Treating physicians estimated likelihood of stones before and after US and CT. Secondary: sensitivity & specificity of US for renal stones29 of 38 stones detected by US. Sensitivity 76% specificity 78% PPV 66% (15 false positives). NPV: 86%Convenience sample – selection bias. US operators not blinded to patient history.
Rosen C, Brown D, Sagarin M et al.
Patients presenting to ED with loin or abdominal pain who had had either IVU or CT ordered to determine if renal stones are present.Prospective Diagnostic study: 126 patients enrolled, 84 had US and IVU, 42 had US and CT. Primary: evaluate sensitivity and specificity of US by ED physicians. Secondary: evaluate how bedside US can be used to predict likelihood of renal stones.Sensitivity 72% specificity 73% as compared to IVU. PPV 85% NPV 54%Convenience sample – 500 patients underwent IVU or CT in time period – only 126 chosen -selection bias possible. IVU considered as gold standard. US operator not blinded to patient history.


The sensitivity, specificity, PPV and NPV for ED physicians was 72-95%, 37-92%, 66-86% and 54-97% respectively. The wide variation in each of these reflects the important difference in operator capability, which was itself well documented by Jang et al (2010) who showed a steady improvement in sensitivity and specificity of residents after completing certain numbers of exams, until after 30 exams the operators were consistently accurate.

Clinical Bottom Line

Emergency physicians with enough experience or training can accurately diagnose hydronephrosis, however a negative result should prompt further investigation.


  1. Gaspari R and Horst K Emergency Ultrasound and Urinalysis in the Evaluation of Flank Pain. Acad Emerg Med 2005; 12(12):1180-4
  2. Jang T, Casey J, Dyne P et al. The Learning Curve of Resident Physicians Using Emergency Ultrasonography for Obstructive Uropathy. Acad Emerg Med 2010; 17(9):1024-7
  3. Kartal M, Eray O, Erdogru T et al. Prospective validation of a current algorithm including bedside US performed by emergency physicians for patients with acute flank pain suspected for renal colic. Emerg Med J 2006; 23:341-4
  4. Moak J, Lyons M, Lindsell C. Bedside Renal Ultrasound in the Evaluation of suspected ureterolithiasis. Am J Emerg Med 2012; 30(1):218-21
  5. Rosen C, Brown D, Sagarin M et al. Ultrasonography by emergency physicians in patients with suspected ureteral colic. J Emerg Med 1998; 16(6):865-70