A preliminary clinical investigation into the potential of blood lead levels to measure bone resorption in patients with skeletal metastases, using ICP-MS

Summary le, accurate and precise method to measure lead levels in whole blood by inductively coupled plasma — mass spectrometry (ICP-MS) has been developed. Blood samples were diluted (1 + 9) with 0.1% v/v Triton X-100 and 0.1% v/v nitric acid, and gave a limit of detection of 0.06 g/l (3sn). Spiking experiments demonstrated recoveries of 100 ± 10% and verification against Seronorm reference and BCR certified reference materials gave experimental values in close agreement to the reference values. The methodology was used to conduct a feasibility study, involving a preliminary clinical investigation to assess the potential of whole blood lead levels as biochemical markers to measure bone resorption in patients with skeletal metastases and receiving treatment. The results from this feasibility study showed that the method remained under analytical control, giving inter and intra assay coefficients of variation of <5%. This feasibility study also showed that the changes in the blood lead levels within individual patients were measurable and in many cases the patientʹs observed clinical performance demonstrated similar trends to the blood lead levels measured over time. Overall the results were encouraging and showed promise. Further and more detailed investigations into the use of lead and other trace metals as biomarkers of bone resorption is warranted.