Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Quantitative Dot Blot Assays to determine Vibrio cholerae O1 Lipopolysaccharide concentration using Monoclonal Antibody

Introduction: Rapid diagnosis is fundamental for epidemiological control of Cholera disease. Contradictorily the gold standard test (stool culture) takes several days. Finlay Vaccine Institute obtained an Immunoagglutination test for rapid diagnosis of Cholera (FCIT), based on a monoclonal antibody anti- LPS O1 coupled to latex particles. FCIT,includes a positive control (LPS O1 Ogawa), which quantification is mandatory to obtain the registration of the test.The objective of the work was to develop a quantitative Dot Blot to determine the LPS O1 concentration in FCIT Positive control, using a peroxidase-conjugated mAb.Materials and Methods: Conjugation of mAb anti LPS O1 to peroxidase enzyme was carry out by periodate method. Quantitation of LPS O1 was accomplish by quantity Dot Blot. For capture Vibrio cholerae 569B Lipopolysaccharides from Sigma, was used as standard of the curve (40 μg/mL to 0.6 μg/mL) and fi ve lots of FCIT positive control were applied as sample. For detection conjugated mAb-HRP was employed at dilution 1:5000. The development of the reaction was carried out using SIGMAFAST™ DAB Tablet. The images were captured using the GS-800 densitometer and the spots density (Int/mm2) were calculated using the ImageJ software. The LPS concentration in positive control lots was calculated employed Ascent Software.Results: The mAb was conjugated to the HRP effi ciently with working dilutions range from 1:2500 to 1:10,000. A four-parameter fi t model curve was obtained with R2 of 0.99. Of the fi ve FCIT positive control lots evaluated, four complied with 30% of the expected concentration, for an 80% effectiveness of the technique.Conclusions: These results suggest that the quantitative Dot Blot using the mAbC anti Vibrio cholerae LPS O1, can be employed for the quantifi cation of LPS in batches of the FCIT positive control, from the purifi cation and production stages, as well as for the stability evaluation.</p