Preferred Minimum: 8 mL whole blood Absolute Minimum: 4 mL whole blood

Atypical Hemolytic-Uremic Syndrome The clinical manifestations of hemolytic-uremic syndrome include hemolytic anemia, thrombocytopenia and acute renal failure. Most cases are associated with epidemics of diarrhea caused by verocytotoxin-producing bacteria. Atypical hemolytic uremic syndrome (aHUS) is a rarer disease. It is not associated with Stx-HUS infection and neither does it present with watery, bloody diarrhea (Warwicker et al., 1998). it can be either sporadic or familial, and has an extremely unfavorable prognosis, with about 50% of persons progressing to ESRD and 25% dying during the acute illness; transplantation in may survivors is unsuccessful (Schieppati et al., 1992; Taylor et al., 2004). Genetic studies have shown that approximately 50% of cases of aHUS are caused by mutations in MCP, CFH and CFI (Caprioli et al., 2006). Identifying the genetic cause of aHUS is extremely important as it can help to direct clinical treatment decisions. Thrombomodulin (THBD) Thrombomodulin, a 575-amino-acid protein encoded by the gene THBD, is an endothelial-cell glycoprotein that is a negative regulator of the complement system. It contains a lectin-like domain that suppresses leukocyte trafficking to prevent inflammation. Mutations in THBD have been found in persons with aHUS. The THBD gene contains 1 exon. Sensitivity is greater than 99%.