The evaluation of a scoring system for diagnosing atypical hemolytic uremic syndrome

Abstract

ObjectiveAlthough the definitive diagnosis of atypical hemolytic uremic syndrome (aHUS) depends on a genetic analysis for the complement factors, such a genetic analysis is time-consuming and expensive. We examined the usefulness of a diagnostic scoring system for aHUS. MethodsThe thrombotic microangiopathy (TMA) scoring system consists of hemoglobin, the platelet count, creatinine levels and organ failure, and the aHUS scoring system consists of past history and family history of TMA, age at onset, prodromal symptoms and “red or brownish urine”, and these scoring system were both evaluated in patients with aHUS, thrombotic thrombocytopenic purpura or secondary TMA. ResultsIn a receiver operating characteristics analysis, an adequate cut-off value for diagnosing aHUS, TTP, other TMA or all TMA versus patients without TMA was 7 points for both TMA screening scores. The area under the curve was 0.965 for the TMA screening score and 0.966 for the aHUS score. An adequate cut-off value for diagnosing aHUS was 2 points for a positive aHUS score, - 3 points for an exclusion aHUS score and 0 points for the total aHUS score. ConclusionThe TMA screening and aHUS score systems are useful for making a diagnosis of aHUS without performing specific laboratory tests.