Many trace elements are known to be essential to man. These have defined biological functions and have clinical symptoms associated with deficiency. Blood levels are higher than serum due to vitamin B12 and related cobalt complexes. High concentrations of cobalt in blood or serum are associated with increased wear of artificial hip joints and may contribute to an indication for revision of the procedure. The MHRA has advised that a concentration of >119 nmol/L is an indication of excessive wear in a metal-on-metal hip implant.
Trace element free (royal blue top)
Well functioning artificial hip joints are associated with the following concentrations of cobalt:
metal-on-metal unilateral: <30 nmol/L
metal-on-metal bilateral: <45 nmol/L
metal-on-plastic: <10 nmol/L