The present invention relates to a method for determining the propensity of a fluid for calcification characterized by the following steps: (i) adding a soluble calcium salt and a soluble phosphate salt to a sample of the fluid; (ii) incubating the sample at conditions allowing the formation of calciprotein particles (CPPs); and (iii) determining one or more of the following: (a) the rate of the formation of primary and/or secondary CPPs; (b) the amount of primary and/or secondary CPPs; and/or (c) the rate of the transition of primary CPPs into secondary CPPs, wherein an increase in one or more of (a), (b) and/or (c) of step (iii) indicates an increased propensity of the fluid for calcification.