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Background We investigated the percentage of patients diagnosed with the correct underlying cause of anaemia by general practitioners when using an extensive versus a routine laboratory work-up. Methods An online survey was distributed among 836 general practitioners. The survey consisted of six cases, selected from an existing cohort of anaemia patients ( n = 3325). In three cases, general practitioners were asked to select the laboratory tests for further diagnostic examination from a list of 14 parameters (i.e. routine work-up). In the other three cases, general practitioners were presented with all 14 laboratory test results available (i.e. extensive work-up). General practitioners were asked to determine the underlying cause of anaemia in all six cases based on the test results, and these answers were compared with the answers of an expert panel. Results A total of 139 general practitioners (partly) responded to the survey (17%). The general practitioners were able to determine the underlying cause of anaemia in 53% of cases based on the routine work-up, whereas 62% of cases could be diagnosed using an extensive work-up ( P = 0.007). In addition, the probability of a correct diagnosis decreased with the patient's age and was also affected by the underlying cause itself, with anaemia of chronic disease being hardest to diagnose ( P = 0.003). Conclusion The use of an extensive laboratory work-up in patients with newly diagnosed anaemia is expected to increase the percentage of correct underlying causes established by general practitioners. Since the underlying cause can still not be established in 31.3% of anaemia patients, further research is necessary.

BackgroundMacrocytic anaemia (MCV ≥ 100 fL) is a relatively common finding in general practice. However, literature on the prevalence of the different causes in this population is limited. The prevalence of macrocytic anaemia and its underlying aetiology were analysed in a general practice population. The potential effect of the different aetiology on survival was also evaluated.MethodsBetween the 1st of February 2007 and the 1st of February 2015, patients aged 50 years or older and presenting to their general practitioner with a newly diagnosed anaemia, were included in the study. Anaemia was defined as haemoglobin level below 13.7 g/dL in men and below 12.1 g/dL in women. A broad range of laboratory tests was performed for each patient. The causes of anaemia were consequently determined by two independent observers based on the laboratory results.ResultsOf the 3324 included patients, 249 (7.5 %) displayed a macrocytic anaemia and were subsequently analysed. An underlying explanation could be established in 204 patients (81.9 %) with 27 patients (13.2 %) displaying multiple causes. Classic aetiology (i.e. alcohol abuse, vitamin B12/folic acid deficiency, haemolysis and possible bone marrow disease) was found in 115 patients. Alternative causes (i.e. anaemia of chronic disease, iron deficiency, renal anaemia and other causes) were encountered in 101 patients. In addition, a notable finding was the median gamma GT of 277 U/L in patients diagnosed with alcohol abuse (N = 24, IQR 118.0-925.5) and 23 U/L in the remaining cohort (N = 138, IQR 14.0-61.0). The distribution of gamma GT values was statistically different (P < 0.001).Five year survival rates were determined for six categories of causes, ranging from 39.9 % (95 % CI 12.9-66.9) for renal anaemia to 76.2 % (95 % CI 49.4-103.0) for the category multiple causes.ConclusionIn addition to classic explanations for macrocytosis, alternative causes are frequently encountered in patients with macrocytic anaemia in general practice.

Background: To study etiologies of anemia using an extensive laboratory analysis in general practices. Method: An extensive laboratory analysis was performed in blood of newly diagnosed anemia patients aged ≥50 years from the general population in the city of Dordrecht area, the Netherlands. Eight laboratory-orientated etiologies of anemia were defined. Patients were assigned one or more of these etiologies on the basis of their test results. Results: Blood of 4152 patients (median age 75 years; 49% male) was analyzed. The anemia etiology was unclear in 20%; a single etiology was established in 59%; and multiple etiologies in 22% of the patients. The most common etiologies were anemia of chronic disease (ACD) (54.5%), iron deficiency anemia (IDA) (19.1%) and renal anemia (13.8%). The most common single etiologies were IDA (82%) and ACD (68%), while the multiple etiologies most commonly included folic acid deficiency (94%) and suspected bone marrow disease (88%). Older age was associated with a lower incidence of IDA and a higher incidence of renal anemia. Mild anemia was more often associated with ACD and uncertain anemia, while severe anemia was mainly seen in patients with IDA. Conclusion: Extensive laboratory analysis in anemic patients from the general population helped clarify the etiology of anemia and revealed many various combinations of etiologies in a significant proportion of patients. Age, sex and the severity of anemia are predictive of the underlying etiology.

Primary cultures of embryonic chick osteoblasts consist of a heterogeneous cell population. Patch clamp measurements were done on 1- to 5-day-old osteoblasts, osteocytes, fibroblastlike cells, and cells that could not be classified on morphologic criteria. The measurements showed the omnipresence of depolarization-activated high-conductance channels in cell-attached patches. The whole-cell experiments showed an outward rectifying conductance activating at positive membrane potentials. Channels underlying the latter conductance were found to be K+ conducting in outside-out membrane patches. The activation potential of the outward rectifying K+ conductance shifted to negative membrane potentials upon increasing the intracellular Ca2+ concentration within the range of 10(-8)-10(-3.2) M. The same happened with the activation potential of the K+ channels found in outside-out patches. Finally, inside-out patch experiments directly demonstrated the dependency of the activation potential of K+ channels on Ca2+ ions. Thus the identity and main characteristics of Ca2(+)-activated K+ channels expressed by the various cell types present in chick osteoblast cultures have now been established. Decreased input resistances were found in cells of cultures more than 2 days old. This is consistent with the establishment of electrical coupling between the cells. Functions in which Ca2(+)-activated K+ channels could play a role are discussed.