Per Winkel

Variation of serum iron concentration in young healthy men: Within-day and day-to-day changes.

1. Serum iron concentration values were determined on a group of 11 healthy young men on blood specimens which were drawn at various hours of the day: 800 h, 1100 h, and 1400 h; on each of four separate days. 2. using a three-way ANOVA (analysis of variance) model, we determined the diurnal variation both for the group as a whole (main hour effect) and for the individual subjects (subject-hour and subject-day-hour interactions). 3. the total combined within-day variation as expressed in coefficients of variation was 12.9% with the peak value seen at 1400 h. 4. on a separate study, blood specimens were obtained at 1100 h on five separate days during a two week period on the same volunteers. 5. using a two-way ANOVA model (subject and day) the day-to-day coefficient of variation was found to be 26.6% for the group. In both cases (within-day and day-to-day) the biological variation was considerably greater than the analytic variation.

Plasma sex hormones and ischemic heart disease

The reason why men have a higher incidence of ischemic heart disease than women, and women rarely develop ischemic heart disease before the menopause, is not known. However, elevated plasma estradiol and estrone concentrations have been found in men surviving myocardial infarction. Hence, hyperestrogenemia has been suggested as a coronary risk factor. To assess this theory we review the literature on sex steroid production, the relationship between established coronary risk factors and plasma sex hormones, as well as results from clinical trials in which estrogens have been administered to men and women. Other possible explanations why plasma estradiol levels are elevated in male survivors of myocardial infarction are discussed. Based on earlier and recent evidence, it is hypothesized that the elevated plasma estradiol concentration found in men surviving myocardial infarction is due to either the myocardial infarction itself or established risk factors such as smoking or hypertension.

Utilization review and management of laboratory testing in the ambulatory setting.

Physicians are probably guilty of misusing the clinical laboratory by either ordering too many tests (overutilization) or ordering too few tests (underutilization). This article is concerned mainly with overutilization in terms of searching for asymptomatic disease, too frequent monitoring of tests, ordering of test clusters, and a failure to use available information. The strategies considered to decrease overutilization include educational strategies, audit with feedback, cost-awareness strategies, rationing strategies, financial incentives and risk-sharing strategies, changes in the test request procedures, and administrative mandates of set protocols for laboratory test ordering.

Daily variation of lipids and hormones in sera of healthy subjects

The physiological day-to-day variation of selected hormone and lipid concentration values in sera of healthy subjects was studied. We drew blood specimens from 14 healthy volunteers, aged 22 to 40 years, (8 male and 6 female) at 0800 h on six separate days over a ten day interval. On one occasion all the twelve specimens from each subject (6 days X 2 replicates) were assayed for the hormones: thyroxine and cortisol; and the lipips: cholesterol and triglyceride which were analyzed by enzymatic methods. The assays were performed on one occasion in order to eliminate the batch-to-batch analytical variation which would tend to blur the physiological day-to-day variation. Using an analysis of variance technique, the total variation was separated into the physiological intraindividual day-to-day variation, the biological inter-individual variation, and the within-batch analytical variation. The mean physiological day-to-day variations in terms of percent coefficient of variation were 7.5% for thyroxine, 26.6% for cortisol, 4.8% for cholesterol, , and 25.0% for triglycerides.

Present and Projected Consumption of Hospital Bed-days as a Function of Terminal Days Before Death

In 1983 the bed-day consumption per year per 1,000 inhabitants was 1,571 for all subjects in the Copenhagen County, and 774, 1,239, and 4,918 for subjects 0-19 years, 20-64 years, and above 65 years of age, respectively. Extrapolating from these data the hospital bed-day consumption per inhabitant is predicted to increase by 20.6% in Denmark by the year 2025 as compared to 1986. The mean hospital bed-day consumption per subject during the last 150 days prior to death in hospital was 25.0 days for males and 29.7 for females. Making the conservative assumption that only subjects who die in hospital consume hospital bed-days during the last 150 days before death, the bed-day consumption during 1983 of 0-64 years old subjects being in the terminal 150-day phase was 5.87% of the total annual bed-day consumption of this age group. For subjects 65 years of age or older, it was 18.1%.