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There are many causes of raised serum ferritin concentrations including iron overload, inflammation and liver disease to name but a few examples. Cases of extreme hyperferritinaemia (serum ferritin concentration equal to or greater than 10 000 ug/l) are being reported in laboratories but the causes of this are unclear. We conducted an audit study to explore this further. Extreme hyperferritinaemia was rare with only 0.08% of ferritin requests displaying this. The main causes of extreme hyperferritinaemia included multiple blood transfusions, malignant disease, hepatic disease and suspected Still's disease.

Aims: To review the incidence of multiple tumour marker (TM) requesting in the primary care setting and determine whether the rationale for requesting a TM panel is in agreement with evidence-based guidelines., Methods: Data-mining software was used to retrospectively identify multiple TM requests and requesting practices of GP surgeries over a 34-month period for α-fetoprotein, CA125, CA15-3, CA19-9, carcinoembryonic antigen and prostate-specific antigen. The appropriateness of each test was reviewed by a clinical biochemist in accordance with National Association of Clinical Biochemistry best-practice guidelines., Results: 505 multiple TM requests were identified which corresponded to 1304 TM tests. Comparison with best-practice guidelines suggested that 68% of request cards contained no appropriate TM request, and 84% of the tests requested were inappropriate., Conclusion: A review of requesting practices in primary care for TMs highlights the need for laboratories to be more proactive in educating their users on their clinical utility and limitations.

A comparison has been made of the radioisotope dilution-coated charcoal method and a microbiological assay (with L. leichmannii as test organism) for determining the concentration of vitamin B(12) in serum. A satisfactory correlation was found between the results of the two methods. Under appropriate conditions the reproducibility of the radioisotope method compared favourably with that of the microbiological method.

An improved and simplified method is described for the measurement of vitamin B(12) in serum using intrinsic factor, (57)CoB(12), and coated charcoal. The extraction of serum in the presence of cyanide and the incorporation of B(12)-deficient serum into the intrinsic factor control has increased the accuracy of the method for both sera and crystalline B(12) solutions. There are interesting differences between the results obtained for some sera by the isotope and L. leichmannii methods and the reasons for these differences are discussed.