Utility of pre-operative haemoglobin concentration to guide peri-operative blood tests for hip and knee arthroplasty: a decision curve analysis 著者: Dhiman, P, Gibbs, VN, Collins, GS, Van Calster, B, Bakhishli, G, Grammatopoulos, G, Price, AJ, Taylor, A, Murphy, MF, Kendrick, BJL, Palmer, AJR