Urine provision remains an important issue in the serum versus urine debate; lack of urine with diagnostic serum samples has repeatedly been reported (Section 23.5). Even once a diagnosis of monoclonal gammopathy has been confirmed, problems with urine provision continue. In a study of 496 newly diagnosed monoclonal gammopathy patients by Holding et al. , only 30% of serum samples had a matched urine sample provided within 7 days; this increased to 57% within 90 days. In a review of 55 multiple myeloma (MM) patients referred for autologous stem cell transplantation between 2006 and 2011, Fidler et al.  noted that 24-hour urine compliance was 55% and apparently falling, while sFLC compliance was slightly better (67%), and appeared to be rising over the same period.
Overall, the annual UK National Pathology Benchmarking Review for 2007/2008 reported that the number of UPE tests performed was much lower than serum protein electrophoresis (SPE), comprising only 14% of SPE requests (298,392) . Recent National guidelines omit the use of urine BJP testing to screen for a monoclonal protein because of poor compliance, and the potential to miss diagnoses (Section 25.7). The authors of a screening study carried out at New Cross Hospital, Wolverhampton, UK, reported an extremely poor provision of matched urine samples (<5%) and concluded that “the debate over the relative merits of the sFLC assay versus uBJP analysis borders on the irrelevant” .