Biomarkers Biomarkers are used to supplement history and clinical exam, especially in children, trial of fertile age and the elderly where diagnosis is difficult. No inflammatory marker alone, including white blood cell (WBC) count, c-reactive protein (CRP) or other novel tests including procalcitonin, can identify appendicitis with high specificity and sensitivity. However, WBC count is obtained in virtually all patients being assessed for appendicitis, where available. A range of novel biomarkers has been suggested over the last decade, including bilirubin, but these lack external validity and repeatedly suffer from low sensitivity, meaning they are unlikely to come into clinical practice. Clinical decision rules/risk scores Each and clinical sign for appendicitis alone has a poor predictive value. However, in combination the predictive ability is much stronger, although not with perfect accuracy. Consequently, a number of clinical risk scores have been developed, the purpose of the clinical scores are to identify low, intermediate or high-risk patients for appendicitis (figure 2), allowing further investigations to be stratified according to risk (figure 3). The most widely used to date is the Alvarado score. A systematic review and pooled diagnostic accuracy study showed that the score has good sensitivity (especially in men) but low specificity, limiting its clinical impact and meaning few surgeons rely on it to guide management above and beyond their own clinical opinion. The predictive ability of each component of the recently derived modified Alvarado score in children is shown in supplemental table 1. Recently the appendicitis inflammatory response score has been developed, and appears to outperform the Alvarado score in accuracy. Transabdominal ultrasonography Initial reliance on ultrasound has been more recently guarded due to moderate sensitivity (86%, 95% confidence interval 0.83-0.88) and specificity (81%, 78%-84%%) shown through pooled diagnostic accuracy of 14 studies, limiting its diagnostic ability. Due to the need for a specialist operator, it is frequently unavailable out of
Biomarkers Biomarkers are used to supplement history and clinical exam, especially in children, of fertile age and the elderly where diagnosis is difficult. No inflammatory marker alone, including white blood cell (WBC) count, c-reactive protein (CRP) or other novel tests including procalcitonin, can identify appendicitis with high specificity and sensitivity. However, WBC count is obtained in virtually all patients being assessed for appendicitis, where available. A range of novel biomarkers has been suggested over the last decade, including bilirubin, but these lack external validity and repeatedly suffer from low sensitivity, meaning they are unlikely to come into clinical practice. Clinical decision rules/risk scores Each and clinical sign for appendicitis alone has a poor predictive value. However, in combination the predictive ability is much stronger, although not with perfect accuracy. Consequently, a number of clinical risk scores have been developed, the purpose of the clinical scores are to identify low, intermediate or high-risk patients for appendicitis (figure 2), allowing further investigations to be stratified according to risk (figure 3). The most widely used to date is the Alvarado score. A systematic review and pooled diagnostic accuracy study showed that the score has good sensitivity (especially in men) but low specificity, limiting its clinical impact and meaning few surgeons rely on it to guide management above and beyond their own clinical opinion. The predictive ability of each component of the recently derived modified Alvarado score in children is shown in supplemental table 1. Recently the appendicitis inflammatory response score has been developed, and appears to outperform the Alvarado score in accuracy. Transabdominal ultrasonography Initial reliance on ultrasound has been more recently guarded due to moderate sensitivity (86%, 95% confidence interval 0.83-0.88) and specificity (81%, 78%-84%%) shown through pooled diagnostic accuracy of 14 studies, limiting its diagnostic ability. Due to the need for a specialist operator, it is frequently unavailable out of trial