Analysis of unintended events in hospitals: inter-rater reliability of constructing causal trees and classifying root causes.

BACKGROUND: Root cause analysis is a method to examine causes of unintended events. PRISMA (Prevention and Recovery Information System for Monitoring and Analysis: is a root cause analysis tool. With PRISMA, events are described in causal trees and root causes are subsequently classified with the Eindhoven Classification Model (ECM). It is important that root cause analysis tools are reliable, because they form the basis for patient safety interventions. OBJECTIVES: Determining the inter-rater reliability of descriptions, number and classifications of root causes. DESIGN: Totally, 300 unintended event reports were sampled from a database of 2028 events in 30 hospital units. The reports were previously analysed using PRISMA by experienced analysts and were re-analysed to compare descriptions and number of root causes (n = 150) and to determine the inter-rater reliability of classifications (n = 150). MAIN OUTCOME MEASURES: Percentage agreement and Cohen's kappa (kappa). RESULTS: Agreement between descriptions of root causes was satisfactory: 54% agreement, 17% partial agreement and 29% no agreement. Inter-rater reliability of number of root causes was moderate (kappa = 0.46). Inter-rater reliability of classifying root causes with the ECM was substantial from highest category level (kappa = 0.71) to lowest subcategory level (kappa = 0.63). Most discrepancies occurred in classifying external causes. CONCLUSIONS: Results indicate that causal tree analysis with PRISMA is reliable. Analysts formulated similar root causes and agreed considerably on classifications, but showed variation in number of root causes. More training on disclosure of all relevant root causes is recommended as well as adjustment of the model by combining all external causes into one category.

Multiplex ligation-dependent probe amplification (MLPA) as a stand-alone test for rapid aneuploidy detection in amniotic fluid cells.

OBJECTIVE: This study aimed to determine the diagnostic application of multiplex ligation-dependent probe amplification (MLPA) as a stand-alone test for targeted detection of common chromosomal aneuploidies (i.e. 13, 18, 21, X and Y) in amniotic fluid cells in routine prenatal clinical practice. METHODS: In this evaluation study, the MLPA test using kit P095 was performed on 1000 consecutive amniotic fluid samples and the results obtained were compared with traditional karyotyping (TK), the gold standard. RESULTS: The absolute specificity and sensitivity of the MLPA test were 100%. The test yielded a rapid reporting time: 94% within three working days and 5% within seven working days. The test failure rate was 0.8%. The percentage of abnormalities undetectable using this specific test was 2.4%: abnormal foetal ultrasound (N=9), increased risk first trimester screening (N=2), advanced maternal age (N=3) or other reason for referral (N=10). These abnormalities can be categorised in clinically significant (N=8), clinically uncertain (N=4) and clinically nonsignificant (N=12). CONCLUSIONS: MLPA P095 is suitable as a stand-alone test for the rapid and efficient detection of the most common chromosomal aneuploidies in routine prenatal clinical practice. A flow chart for integrating the MLPA test into the cytogenetic laboratory workflow is presented.