Retrospective Evaluation of the Diagnostic Accuracy of the Modified Alvarado Scoring System (MASS) in a Croatian Hospital

Abstract

<p><strong>Objective. </strong>Diagnosing acute appendicitis (AA) is challenging and this has stimulated surgeons to develop scoring systems that could potentially decrease the rate of misdiagnosis in patients with suspected appendicitis. One of the most widely used today is the Modified Alvarado scoring system (MASS), however its sensitivity and specificity varies a great deal between studies. As a result, we wanted to assess the diagnostic accuracy of MASS retrospectively at our institution to achieve the highest possible value of sensitivity and decrease the number of false negative patients.</p><p><strong>Material and Methods. </strong>We retrospectively calculated MASS for all subsequent patients who had undergone an appendectomy at our institution between July 2015 and March 2017.</p><p><strong>Results. </strong>In 118 out of 146 operated patients, AA was confirmed intraoperatively. There was a statistically significant difference between the average MASS score in the positive and negative appendectomy groups (6 v. 4, respectively, P<0.001), with a significantly higher number of females among the negative appendectomies (P<0.001). When lowering the cut-off to a value as low as ≥3, the sensitivity of the MASS score increased to 97.45% (95% CI: 92.7 – 99.5), thus obtaining a very low false negative rate of merely 2.55%.</p><p><strong>Conclusion. </strong>This retrospective diagnostic accuracy study confirmed the higher average MASS score in the group of patients with confirmed AA diagnosis. A MASS score above the proposed low cut-off value (≥3) can be a useful tool to help surgeons ruling in patients with AA in order to reduce the risk of missing diagnosis.</p>

The role of blood inflammatory markers in the preoperative diagnosis of acute appendicitis

“…13 Alvarado score has a modified version: modified Alvarado scoring system (MASS). 14 Memon and his colleagues evaluate the usefulness of the Alvarado scoring system in reducing the percentage of negative appendectomy and found that the sensitivity and specificity of the Alvarado scoring system were 93.5% and 80.6% respectively. The positive and negative predictive values were 92.3% and 83.3%, respectively, and the accuracy was 89.8%.…”

“…In one study, the sensitivity and specificity of the Alvarado score were 83.3% and 41%, respectively 13 . Alvarado score has a modified version: modified Alvarado scoring system (MASS) 14 …”

“…Regarding AA, there are novel findings regarding blood count, including increased absolute neutrophil count, decreased lymphocyte count, and increased platelet count. 14…”

“…Furthermore, several studies show that we can rule out AA in the presence of normal biomarkers. Regarding AA, there are novel findings regarding blood count, including increased absolute neutrophil count, decreased lymphocyte count, and increased platelet count 14 …”