AimTo test the interrater reliability of the modified Oulu Patient Classification instrument, using a multiple parallel classification method based on oral case presentations in home health care in Norway.DesignReliability study.MethodsData were collected at two municipal home healthcare units during 2013–2014. The reliability of the modified OPCq instrument was tested using a new multiple parallel classification method. The data material consisted of 2 010 parallel classifications, analysed using consensus in per cent and Cohen's kappa. Cronbach's alpha was used to measure internal consistency.ResultsFor parallel classifications, consensus varied between 64.78–77.61%. Interrater reliability varied between 0.49–0.69 (Cohen's kappa), the internal consistency between 0.81–0.94 (Cronbach's alpha). Analysis of the raw scores showed 27.2% classifications had the same points, 39.1% differed one point, 17.9% differed two points and 16.5% differed ≥3 points.