[1] Countess Chester NHS Trust, Dept Chem Pathol, Chester CH2 1BQ, Cheshire, England
[2] Hope Hosp, Dept Orthopaed, Salford M6 8HD, Lancs, England
[3] Warrington Dist Gen Hosp, Dept Clin Biochem, Warrington WA5 1QG, Cheshire, England
[4] Manchester Royal Infirm, Dept Clin Biochem, Manchester M13 9WL, Lancs, England