Impact of routine contrast-enhanced CT on costs and use of hospital resources in patients with acute abdomen. Results of a randomised clinical trial

Trends in non-focal neurological chief complaints and CT angiography utilization among adults in the emergency department

Prudent imaging use is essential for cost reduction and efficient patient triage. Recent efforts have focused on head and neck CTA in patients with emergent concerns for non-focal neurological complaints, but have failed to demonstrate whether increases in utilization have resulted in better care. The objective of this study was to examine trends in head and neck CTA ordering and determine whether a correlation exists between imaging utilization and positivity rates. This is a single-center retrospective observational study at a quaternary referral center. This study includes patients presenting with headache and/or dizziness to the emergency department between January 2017 and December 2021. Patients who received a head and neck CTA were compared to those who did not. The main outcomes included annual head and neck CTA utilization and positivity rates, defined as the percent of scans with attributable acute pathologies. Among 24,892 emergency department visits, 2264 (9.1%) underwent head and neck CTA imaging. The percentage of patients who received a scan over the study period increased from 7.89% (422/5351) in 2017 to 13.24% (662/5001) in 2021, representing a 67.4% increase from baseline (OR, 1.14; 95% CI 1.11-1.18; P < .001). The positivity rate, or the percentage of scans ordered that revealed attributable acute pathology, dropped from 16.8% (71/422) in 2017 to 10.4% (69/662) in 2021 (OR, 0.86; 95% CI 0.79-0.94; P = .001), a 38% reduction in positive examinations. Throughout the study period, there was a 67.4% increase in head and neck CTA ordering with a concomitant 38.1% decrease in positivity rate.

Positive oral contrast material for CT evaluation of non-traumatic abdominal pain in the ED: prospective assessment of diagnostic confidence and throughput metrics

OBJECTIVE

Evaluate the impact of positive oral contrast material (POCM) for non-traumatic abdominal pain on diagnostic confidence, diagnostic rate, and ED throughput.

MATERIALS AND METHODS

ED oral contrast guidelines were changed to limit use of POCM. A total of 2,690 abdominopelvic CT exams performed for non-traumatic abdominal pain were prospectively evaluated for diagnostic confidence (5-point scale at 20% increments; 5 = 80-100% confidence) during a 24-month period. Impact on ED metrics including time from CT order to exam, preliminary read, ED length of stay (LOS), and repeat CT scan within 7 days was assessed. A subset of cases (n = 729) was evaluated for diagnostic rate. Data were collected at 2 time points, 6 and 24 months following the change.

RESULTS

A total of 38 reviewers were participated (28 trainees, 10 staff). 1238 exams (46%) were done with POCM, 1452 (54%) were performed without POCM. For examinations with POCM, 80% of exams received a diagnostic confidence score of 5 (mean, 4.78 ± 0.43; 99% ≥ 4), whereas 60% of exams without POCM received a score of 5 (mean, 4.51 ± 0.70; 92% ≥ 4; p < .001). Trainees scored 1,523 exams (57%, 722 + POCM, 801 -POCM) and showed even lower diagnostic confidence in cases without PCOM compared with faculty (mean, 4.43 ± 0.68 vs. 4.59 ± 0.71; p < 0.001). Diagnostic rate in a randomly selected subset of exams (n = 729) was 54.2% in the POCM group versus 56.1% without POCM (p < 0.655). CT order to exam time decreased by 31 min, order to preliminary read decreased by 33 min, and ED LOS decreased by 30 min (approximately 8% of total LOS) in the group without POCM compared to those with POCM (p < 0.001 for all). 205 patients had a repeat scan within 7 days, 74 (36%) had IV contrast only, 131 (64%) had both IV and oral contrast on initial exam. Findings were consistent both over a 6-month evaluation period as well as the full 24-month study period.

CONCLUSION

Limiting use of POCM in the ED for non-traumatic abdominal pain improved ED throughput but impaired diagnostic confidence, particularly in trainees; however, it did not significantly impact diagnostic rates nor proportion of repeat CT exams.

Transvaginal US vs. CT in non-pregnant premenopausal women presenting to the ED: clinical impact of the second examination when both are performed

Objective

To determine the clinical impact of the second examination when both CT and TVUS are obtained in the same ED visit for acute pelvic/lower abdominal symptoms in non-pregnant premenopausal women.

Methods

200 consecutive non-pregnant premenopausal women (mean age, 31.8 years; range, 18–49 years) who underwent both ED-based TVUS and abdominopelvic CT evaluation for acute symptoms over a 12 month period were included; 107 women had TVUS first, followed by CT; 93 women had CT first. All relevant clinical, radiologic, and pathologic findings were reviewed to establish a final diagnosis. Any additional clinical impact provided by the second imaging test was assessed by two experienced abdominal radiologists.

Results

Initial TVUS was interpreted as normal (n = 63) or mentioned incidental findings (n = 11) in 69% (74/107); subsequent CT established a non-gynecologic GI/GU etiology in 25 (34%). For 37% (34/93) of CT exams interpreted as normal, TVUS added no new information. In 32 cases (34%), TVUS further excluded ovarian torsion/adnexal pathology when initial CT was indeterminate/equivocal. Overall, CT following TVUS provided a key new or alternative diagnosis in 26% (28/107), whereas TVUS after CT provided a relevant new/alternative diagnosis in only 1/93 cases (p < 0.001). In nine cases (8%), CT confirmed a positive US diagnosis but detected relevant additional diagnostic information.

Conclusion

CT following negative TVUS frequently identified a non-gynecologic cause of acute pelvic or lower abdominal symptoms in non-pregnant premenopausal women, whereas the main benefit of TVUS after CT was more confident exclusion of ovarian torsion.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00261-022-03504-6.

Reducing length of stay for patients presenting to general surgery with acute non-surgical abdominal pain

BACKGROUND

Acute abdominal pain is a common surgical presentation. We previously found that over the last decade, more patients were admitted to hospital with non-surgical diagnoses (e.g. gastroenteritis, constipation and non-specific abdominal pain) and length of stay and use of imaging (mainly computed tomography scan) for these patients increased. This study aimed to reduce length of stay and use of imaging for patients admitted with non-surgical abdominal pain.

METHODS

A prospective study was undertaken in a tertiary centre evaluating length of stay and use of additional imaging in patients with a non-surgical diagnosis after a quality improvement intervention was implemented.

RESULTS

A total of 454 patients were included; 204 (44.9%) presented with non-surgical abdominal pain. During the study period, a significant reduction in computed tomography scan requests was observed (38.5-25.0%, P = 0.037) and an increasing proportion of these patients were discharged within 12 h (33.3-57.1%, P = 0.018). The number of re-presentations remained unchanged (P = 0.358).

CONCLUSIONS

The study intervention increased the proportion of patients with non-surgical diagnoses that were successfully discharged within 12 h and reduced the use of additional imaging in this group. This may lead to improved use of health care resources for patients with more urgent diagnoses.

Routine versus selective computed tomography in non-traumatic acute abdominal pain: meta-analysis of randomised trials

PURPOSE

To compare the routine vs. selective use of computed tomography (CT) in patients presenting with non-traumatic acute abdominal pain (AAP) to a surgical service.

METHODS

We conducted a systematic review of literature and meta-analysis of outcomes according to PRISMA statement standards to compare the routine vs. selective use of CT in adult patients presenting with non-traumatic AAP.

RESULTS

Analysis of 722 patients from 4 randomised controlled trials showed no difference between the routine CT and selective CT groups in terms of proportion of correct diagnoses (OR 1.36,95% CI 0.89, 2.07, P = 0.15), mortality (RD 0.03, 95% CI - 0.08, 0.02, P = 0.27] and length of hospital stay (LOS) [MD - 0.26, 95% CI - 2.07, 1.55, P = 0.78).

CONCLUSIONS

The routine use of CT does not improve the proportion of correct diagnoses and mortality compared to selective use of CT in adult patients with non-traumatic AAP. The available evidence regarding the influence of routine CT on LOS may be subject to type 2 error. These findings, however, may not apply to the elderly patient with AAP and further studies are required.

Diagnostic imaging for acute abdominal pain in an Emergency Department in Italy

Imaging plays a key role in the diagnostic work-up of patients with non-traumatic acute abdominal pain (AAP) in emergency department (ED). We aimed to evaluate the use and diagnostic performance of imaging techniques in adult patients with AAP in an ED in Italy. Patients with non-traumatic AAP admitted at the ED of S. Orsola-Malpighi University Hospital of Bologna (Italy) from the 1st to the 30th November 2016 were included. Demographic and clinical data, data on radiological procedures and discharge diagnosis were collected. Sensitivity and specificity for detecting acute diseases were assessed using the discharge diagnosis from the ED as reference standard. Of the 578 patients (female 52.8%, mean age 51.3 years) admitted to the ED for AAP, 433 (74.9%) underwent abdominal imaging. The most frequent techniques used were abdominal plain radiography and ultrasonography (US), performed in 38.4% and 37.9% of patients, respectively, followed by computed tomography (CT) in 28% of patients. Plain radiography yielded a sensitivity of 28% and specificity of 91.1%; the sensitivity increased to 79.4% in patients with small bowel obstruction. Ultrasonography's sensitivity and specificity were 61.8% and 98.4%, respectively; the sensitivity of US reached 85.2% and 90% in patients with acute cholecystitis/biliary colic and urolithiasis, respectively. The sensitivity and specificity of CT were 87.8% and 92.9%, respectively. Plain radiography is still overused in the diagnostic work-up of AAP in ED in Italy, despite its unsatisfactory sensitivity. Ultrasonography and CT has a higher sensitivity and should be used as first-level imaging in most patients.

Incidence and significance of injuries on secondary CT imaging after initial selective imaging in blunt trauma patients

OBJECTIVE

It is unclear if additional computerized tomography (CT) imaging is warranted after injuries are identified on CT in blunt trauma patients. The objective of this study was to determine the incidence and significance of injuries identified on secondary CT imaging after identification of injuries on initial CTs in blunt trauma patients.

METHODS

This was a retrospective cohort study at an academic Level 1 trauma center with a two-tiered trauma system.

INCLUSION CRITERIA

age ≥ 18, level 2 trauma activation, injury identified on initial CT, and secondary CTs ordered. Secondary injuries were categorized as resulting in: no changes, minor changes, or major changes in management.

RESULTS

537 patients underwent 1179 initial CT scans which identified 744 injuries. There were 1094 secondary CTs which identified 143 additional injuries in 94 (18%) patients. 9 (1.7%) patients had at least one major management change and 64 (12%) had at least one minor management change. Rib fracture(s) was the most common injury on secondary scans [45/143 (32%)]. The major management changes were: tube thoracostomy for pneumothorax (4 patients), blood transfusion for hemoperitoneum (1 patient), surgery for acetabular fracture (1 patient), thoracolumbar brace for spine fracture (2 patients) and angiography for splenic injury (1 patient).

CONCLUSION

While a significant proportion of patients (18%) had injuries on secondary CT, only 1.7% of patients had a resultant major management change. Future research is warranted to determine the need for additional CT imaging after an initial selective imaging strategy in blunt trauma patients.

Systematic review of diagnostic pathways for patients presenting with acute abdominal pain

Purpose

Abdominal pain is the most common reason for surgical referral. Imaging, aids early diagnosis and treatment. However unnecessary requests are associated with increased costs, radiation exposure and increased length of stay. Pathways can improve the quality of the diagnostic process. The aim of this systematic review was to identify the current evidence for diagnostic pathways and their use of imaging and effect on final outcomes.

Data sources

A systematic search of Embase, Medline and Cochrane databases was performed using keywords and MeSH terms for abdominal pain.

Study selection

All papers describing a pathway and published between January 2000 and January 2017 were included.

Data extraction

Data was obtained about the use of imaging, complications and length of stay. Quality assessment was performed using MINORS and Level of Evidence.

Results

Ten articles were included, each describing a different pathway. Five studies based the pathway on literature reviews alone and five studies on the results of their prospective study. Of the latter five studies, four showed that routine imaging increased diagnostic accuracy, but without showing a reduction in length of stay, complication rate or mortality. None of the studies included evaluated use of hospital resources or costs.

Conclusion

Pathways incorporating routine imaging will improve early diagnosis, but has not been proven to reduce complication rates or hospital length of stay. On the basis of this systematic review conclusions can therefore not be drawn about the pathways described and their benefit to the diagnostic process for patients presenting with abdominal pain.

Can Surgical Registrars Accurately Identify the Urgent from the Non-Urgent Patient Presenting with Acute Abdominal Pain?

BACKGROUND

Acute abdominal pain is a common surgical presentation with a wide range of causes. Differentiating urgent patients from non-urgent patients is important to optimise patient outcomes and the use of hospital resources. The aim of this study was to determine how accurately urgent and non-urgent patients presenting with abdominal pain can be identified.

METHODS

A prospective study of consecutive patients admitted with abdominal pain was undertaken. Urgent patients were classified as requiring treatment (theatre, intensive care unit, endoscopy, or radiologic drainage) within 24 h. Differentiation between urgent and non-urgent was made on the basis of the initial assessment prior to the use of advanced imaging. Outcomes were compared to a final classification based on final diagnosis as adjudicated by an expert panel.

RESULTS

Of the 301 patients included, 93 (30.9%) were deemed urgent based on initial assessment, compared to 83 (27.6%) on final diagnosis. Overall sensitivity for recognising urgent patients was 74.7% and specificity 89.9%, and overall accuracy was higher for senior registrars compared to junior registrars (p = 0.015). Urgent patients more often looked unwell or had peritonism on examination (39.8 vs. 17.4% and 56.6 vs. 14.7%, respectively, p < 0.001 for both).

CONCLUSIONS

Registrars can accurately differentiate urgent from non-urgent patients with acute abdominal pain in the majority of cases. Accuracy was higher amongst senior registrars. The "end-of-the-bed-o-gram" and clinical examination are the most important features used for making this differentiation. This demonstrates that there is no substitute for exposure to acute presentations to improve a trainee's diagnostic skill.

Concomitant leukocytosis and lymphopenia predict significant pathology at CT of acute abdomen: a case-control study

BACKGROUND

Acute abdominal pain accounts for about 10% of emergency department visits and has progressively become the primary indication for CT scanning in most centers. The goal of our study is to identify biological or clinical variables able to predict or rule out significant pathology (conditions requiring urgent medical or surgical treatment) on abdominal CT in patients presenting to an emergency department with acute abdominal pain.

METHODS

This was a retrospective cohort study performed in the emergency department of an academic center with an annual census of 60'000 patients. One hundred and-nine consecutive patients presenting with an acute non-traumatic abdominal pain, not suspected of appendicitis or renal colic, during the first semester of 2013, who underwent an abdominal CT were included. Two medical students, completing their last year of medical school, extracted the data from patients' electronic health record. Ambiguities in the formulations of clinical symptoms and signs in the patients' records were solved by consulting a board certified emergency physician. Nine clinical and biological variables were extracted: shock index, peritonism, abnormal bowel sounds, fever (> 38 °C), intensity and duration of the pain, leukocytosis (white blood cell count >11G/L), relative lymphopenia (< 15% of total leukocytes), and C-reactive Protein (CRP). These variables were compared to the CT results (reference standard) to determine their ability to predict a significant pathology.

RESULTS

Significant pathology was detected on CT in 71 (65%) patients. Only leukocytosis (odds ratio 3.3, p = 0.008) and relative lymphopenia (odds ratio 3.8, p = 0.002) were associated with significant pathology on CT. The joint presence of these two anomalies was strongly associated with significant pathology on CT (odds ratio 8.2, p = 0.033). Leukocytosis with relative lymphopenia had a specificity of 89% (33/37) and sensitivity of 48% (33/69) for the detection of significant pathology on CT.

CONCLUSION

The high specificity of the association between leukocytosis and relative lymphopenia amongst the study population suggests that these parameters would be sufficient to justify an emergency CT. However, none of the parameters could be used to rule out a significant pathology.

Appropriateness of CT scans for patients with non-traumatic acute abdominal pain

OBJECTIVE

Acute abdominal pain is the most common reason for surgical admission. CT scans are increasingly used to aid early diagnosis. Excessive use of CT scans is associated with increased length of stay, healthcare costs and radiation. The aim of this study was to evaluate the appropriateness of CT scans for patients presenting with acute abdominal pain.

METHODS

We examined 100 consecutive patients presenting with new acute abdominal pain who underwent a CT scan. Clinical information available at the time the scan was ordered, was summarised and reviewed independently by five consultant general surgeons and five consultant radiologists.

RESULTS

A CT scan was judged to be not indicated in a median of 21% of cases (range 12-53%), more information was required in a median of 16% (0-41%) and in a median of 58% (37-88%) the CT scan was considered indicated. There was a good level of agreement (Cronbach's α 0.704) across the 10 experts.

CONCLUSION

These data suggest that a large proportion of CT scans for patients with acute abdominal pain are not clinically indicated or are being performed prior to adequate clinical work-up. Optimising CT scan requests for this patient group will improve use of healthcare resources. Advances in knowledge: Both radiologists and general surgeons agree that there is no indication for an abdominal CT scan for a patient presenting with acute abdominal pain in a median of 21% of the cases.

Utility of multiple rule out CT screening of high-risk atraumatic patients in an emergency department-a feasibility study

BACKGROUND

Several large trials have evaluated the effect of CT screening based on specific symptoms, with varying outcomes. Screening of patients with CT based on their prognosis alone has not been examined before. For moderate-to-high risk patients presenting in the emergency department (ED), the potential gain from a CT scan might outweigh the risk of radiation exposure. We hypothesized that an accelerated "multiple rule out" CT screening of moderate-to-high risk patients will detect many clinically unrecognized diagnoses that affect change in treatment.

METHOD

Patients ≥ 40 years, triaged as high-risk or moderate-to-high risk according to vital signs, were eligible for inclusion. Patients were scanned with a combined ECG-gated and dual energy CT scan of cerebrum, thorax, and abdomen. The impact of the CT scan on patient diagnosis and treatment was examined prospectively by an expert panel.

RESULTS

A total of 100 patients were included in the study, (53% female, mean age 73 years [age range, 43-93]). The scan lead to change in treatment or additional examinations in 37 (37%) patients, of which 24 (24%) were diagnostically significant, change in acute treatment in 11 (11%) cases and previously unrecognized malignant tumors in 10 (10%) cases. The mean size specific radiation dose was 15.9 mSv (± 3.1 mSv).

CONCLUSION

Screening with a multi-rule out CT scan of high-risk patients in an ED is feasible and result in discovery of clinically unrecognized diagnoses and malignant tumors, but at the cost of radiation exposure and downstream examinations. The clinical impact of these findings should be evaluated in a larger randomized cohort.

Non-specific abdominal pain remains as the most common reason for acute abdomen: 26-year retrospective audit in one emergency unit

OBJECTIVE

Distribution of diagnoses causing acute abdominal pain (AAP) may change because of population aging, increased obesity, advanced diagnostic imaging and changes in nutritional habits. Our aim was to evaluate the diagnoses causing AAP during a 26-year period.

MATERIALS AND METHODS

This was a retrospective cross-sectional cohort study in one emergency department (ED) covering population about 250,000. All patients admitted to the ED in 1986, 2003 and 2012 were evaluated from hospital electronic database. Demographic data, utilization of diagnostic tests, surgical treatment and discharge diagnosis were analyzed. Statistical data of population aging, obesity and alcohol consumption during 1980-2012 were obtained from national registers.

RESULTS

The AAP patients represented 10-20% of our total ED census. The most common causes of AAP were nonspecific abdominal pain (NSAP, 31-37%), acute appendicitis (11-23%), biliary disease (9-11%), bowel obstruction (5-7%), acute pancreatitis (4-8%) and acute diverticulitis (1-7%). The percentage of NSAP remained highest throughout the study period. Decrease in the number of acute appendicitis (from 23 to 11%; p < .0001), increase in acute diverticulitis (from 1 to 5%; p ≤ .0001) and acute pancreatitis (from 4 to 7%; p = .0273) was observed over time. The utilization of diagnostic imaging increased significantly (CT from 2 to 37% and US from 4 to 38%, p < .0001). Hospital mortality was very low (1-2%).

CONCLUSIONS

NSAP is still the main differential diagnostic problem in the ED. Except acute appendicitis, distribution of specific diagnoses causing AAP remained rather stable through 26-year audit.

Performance of imaging studies in patients with suspected appendicitis after stratification with adult appendicitis score

Background

Diagnostic scoring is used to stratify patients with suspected appendicitis into three groups: high, intermediate, and low probability of appendicitis. The stratification can be used for selective imaging to avoid the harms of radiation without compromising diagnostic accuracy.

The aim was to study how stratification by Adult Appendicitis Score affects diagnostic performance of imaging studies.

Methods

Analysis of 822 patients who underwent diagnostic imaging for suspected appendicitis was made. Adult Appendicitis Score was used to stratify patients into groups of high, intermediate, and low probability of appendicitis. Diagnostic performance of computed tomography (CT) and ultrasound (US) was compared between these patient groups.

Results

After scoring, pre-test probability of appendicitis ranged from 9-16% in low probability group to 75-79% in high probability group in patients who underwent US or CT. Post-test probability of appendicitis after positive CT was 99, 91, and 75% in high probability, intermediate probability and low probability groups, respectively, p < 0.001. After positive US the respective probabilities were 95, 91 and 42%, p < 0.001.

Conclusion

Diagnostic imaging has limited value in patients with low probability of appendicitis according to Adult Appendicitis Score.

Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain: prospective study and systematic review

OBJECTIVES

Abdominal radiography is frequently used in acute abdominal non-traumatic pain despite the availability of more advanced diagnostic modalities. This study evaluates the diagnostic accuracy of low-dose CT compared with abdominal radiography, at similar radiation dose levels.

METHODS

Fifty-eight patients were imaged with both methods and were reviewed independently by three radiologists. The reference standard was obtained from the diagnosis in medical records. Sensitivity and specificity were calculated. A systematic review was performed after a literature search, finding a total of six relevant studies including the present.

RESULTS

Overall sensitivity with 95 % CI for CT was 75 % (66-83 %) and 46 % (37-56 %) for radiography. Specificity was 87 % (77-94 %) for both methods. In the systematic review the overall sensitivity for CT varied between 75 and 96 % with specificity from 83 to 95 % while the overall sensitivity for abdominal radiography varied between 30 and 77 % with specificity 75 to 88 %.

CONCLUSIONS

Based on the current study and available evidence, low-dose CT has higher diagnostic accuracy than abdominal radiography and it should, where logistically possible, replace abdominal radiography in the workup of adult patients with acute non-traumatic abdominal pain.

KEY POINTS

• Low-dose CT has a higher diagnostic accuracy than radiography. • A systematic review shows that CT has better diagnostic accuracy than radiography. • Radiography has no place in the workup of acute non-traumatic abdominal pain.

Right Lower Quadrant Pain in a Young Female: Ultrasound Diagnosis of Rectus Abdominis Tear

BACKGROUND

Right lower quadrant pain in young females presents a frequent diagnostic challenge for emergency physicians, with a broad differential and several important diagnoses. Using an "ultrasound first" imaging strategy can help decrease the use of computed tomography scans, with associated savings in radiation exposure, cost, and other resource use.

CASE REPORT

We report a case of right lower quadrant pain in a young woman. After her initial history and physical examination, appendicitis was the leading differential. A bedside ultrasound was performed, leading to the uncommon diagnosis of rectus abdominis muscle tear. The sonographic findings of a muscle tear include increase in size, loss of linear, homogeneous architecture, and decreased echogenicity. Making this diagnosis at the bedside using ultrasound obviated the need for further imaging, avoiding unnecessary radiation exposure, and decreasing emergency department length of stay and overall cost, while leading to a tailored treatment plan. Why Should an Emergency Physician Be Aware of This? Rectus abdominis tear is a cause of right lower quadrant pain that may mimic appendicitis and should be considered in patients with this complaint. The ability to make this diagnosis with bedside ultrasound may assist in several important patient-oriented outcomes.

Impact of clinical experience and diagnostic performance in patients with acute abdominal pain

Background. The aims were to evaluate the importance of the formal competence of the emergency department physician, the patient's time of arrival at the emergency department, and the use of a structured schedule for investigation of patients with acute abdominal pain. Methods. Patients attending the Mora Hospital with acute abdominal pain from 1997 to 2000 were registered prospectively according to a structured schedule. Registration included history, symptoms, signs, preliminary diagnosis, surgery and final diagnosis after at least one year.  Results. 3073 acute abdominal pain patients were included. The preliminary diagnosis, as compared with the final diagnosis, was correct in 54% (n = 1659). Previously, during 1996, a base-line registration of 790 patients had a 58% correct diagnoses  (n = 458). A majority of the patients (n = 2699; 88%) were managed by nonspecialists. The proportion of correct diagnoses was 54% (n = 759) for pre-registrar house officers and 55% (n = 443) for senior house officers. Diagnostic performance at the emergency department was independent of patient's time of arrival. Conclusions. A structured schedule for investigation did not improve the diagnostic precision at the emergency department in patients with acute abdominal pain. The diagnostic performance was independent of the formal competence of the physician and the patient's time of arrival.