Sex hormones and risk of breast cancer in premenopausal women: a collaborative reanalysis of individual participant data from seven prospective studies.

BACKGROUND: Associations between circulating concentrations of oestrogens, progesterone, and androgens with breast cancer and related risk factors in premenopausal women are not well understood. We aimed to characterise these associations with a pooled analysis of data from seven studies. METHODS: Individual participant data for prediagnostic sex hormone and sex hormone-binding globulin (SHBG) concentrations were contributed from seven prospective studies. We restricted analyses to women who were premenopausal and younger than 50 years at blood collection, and to women with breast cancer diagnosed before age 50 years. We estimated odds ratios (ORs) with 95% CIs for breast cancer associated with hormone concentrations by conditional logistic regression in cases and controls matched for age, date of blood collection, and day of cycle, with stratification by study and further adjustment for cycle phase. We examined associations of hormones with risk factors for breast cancer in control women by comparing geometric mean hormone concentrations in categories of these risk factors, adjusted for study, age, phase of menstrual cycle, and body-mass index (BMI). All statistical tests were two-sided. FINDINGS: We included data for up to 767 women with breast cancer and 1699 controls in the risk analyses. Breast cancer risk was associated with a doubling in concentrations of oestradiol (OR 1·19, 95% CI 1·06-1·35), calculated free oestradiol (1·17, 1·03-1·33), oestrone (1·27, 1·05-1·54), androstenedione (1·30, 1·10-1·55), dehydroepiandrosterone sulphate (1·17, 1·04-1·32), testosterone (1·18, 1·03-1·35), and calculated free testosterone (1·08, 0·97-1·21). Breast cancer risk was not associated with luteal phase progesterone (doubling in concentration OR 1·00, 95% CI 0·92-1·09), and adjustment for other factors had little effect on any of these ORs. Cross-sectional analyses in control women showed several associations of sex hormones with breast cancer risk factors. INTERPRETATION: Circulating oestrogens and androgens are positively associated with the risk for breast cancer in premenopausal women.

The effects of a high-fruit and -vegetable, high-fiber, low-fat dietary intervention on serum concentrations of insulin, glucose, IGF-I and IGFBP-3.

OBJECTIVE: To determine the effects of dietary change on serum concentrations of insulin, glucose, IGF-I and IGFBP-3. SUBJECTS: From among participants in a randomized clinical trial of men and women without a history of diabetes who were 35 years old or older and who had at least one histologically confirmed colorectal adenoma removed during a qualifying colonoscopy within the 6 months before randomization, 750 subjects were selected for this analysis. METHODS: The authors analyzed fasting serum from 375 subjects with and 375 subjects without a recurrent polyp among participants in a randomized trial of a low-fat (20% of energy), high-fiber (18 g per 1000 kcals of energy intake) and high-fruit and -vegetable (5-8 servings per day) dietary intervention. RESULTS: After 4 years of follow-up, IGF-I concentration in the intervention group (N=248) declined by 8.86 ng/ml (initial mean of 133 ng/ml) and 7.74 ng/ml (initial mean value of 139 ng/ml) in the non-intervention group (N=502). Based on an unpaired t-test, these declines were both statistically significant, but the difference between groups for the decline in IGF-I (1.12 ng/ml ((95% confidence interval, -3.24 to 5.48)) was not. After 4 years, concentrations of IGFBP-3, insulin and glucose were not statistically different from values at baseline, and there were no differences in these serum measures between the intervention and control groups. In analysis restricted to lean (body mass index <25 kg/m(2)) subjects only, however, glucose concentrations in the intervention group decreased by 0.28 mmol/l, while they increased in the control group by 0.01 mmol/l (t-test for mean differences P=0.0003) over 4 years. CONCLUSIONS: A low-fat, high-fiber, high-fruit and -vegetable dietary intervention had minimal impact on serum concentrations of insulin, glucose, IGF-I and IGFBP-3 overall, but in lean subjects the intervention resulted in a significant reduction in serum glucose concentration.

Leukocyte degranulation and vacuole formation in patients with chronic granulomatous disease of childhood.

A cellular defect associated with decreased bactericidal activity of the polymorphonuclear leukocyte has been found in a 2(1/2) yr old Negro boy with the typical clinical and pathological findings of chronic granulomatous disease. Unlike previously described patients his polymorphonuclear leukocytes were shown to undergo apparently normal degranulation and vacuole formation after phagocytosis. Metabolic studies of the leukocytes indicated a failure to increase oxygen consumption with phagocytosis or to reduce Nitroblue tetrazolium dye. These metabolic abnormalities are identical with those previously reported in patients with chronic granulomatous disease. Two additional patients with chronic granulomatous disease have also been found to have apparently adequate degranulation of polymorphonuclear leukocytes after phagocytosis. Our studies suggest that failure of degranulation may not be a necessary part of this functional leukocyte abnormality.

Association of change in body mass with breast cancer.

We examined the relation between maximal adult change in body mass and breast cancer in the Epidemiological Follow-up Study of the first National Health and Nutrition Examination Survey. A total of 5599 women ages 25 to 74 years at the baseline examination in 1971 to 1975 were analyzed. Adult body mass change was calculated from baseline interview questions on lowest and highest adult weights, ages at those weights, and adult height. The cohort was followed for a median of 10 years and yielded 101 cases of breast cancer. In a multivariate model adjusting for potential confounders (age, body mass, education, parity, age at first birth, menopausal status, calorie and alcohol intake, and physical activity) the relative risk estimates for the upper two tertiles of body mass gain were 1.7 (95% confidence interval, 0.9 to 3.4) and 2.5 (95% confidence interval, 1.2 to 5.4), respectively, in comparison to the lowest tertile of adult body mass gain. The relative risk estimate for those with a loss in body mass during adulthood was 1.3 (95% confidence interval, 0.7 to 2.6) in comparison to those in the lowest tertile of adult body mass gain. There was no association between body mass at the baseline examination and subsequent breast cancer. The results of this study suggest that gain in adult body mass is a predictor of breast cancer risk independent of adult body mass. These results also suggest that avoidance of marked weight gain during adult life may reduce the risk of breast cancer.

Serum vitamin A and subsequent development of prostate cancer in the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study.

The relation between serum vitamin A measurements made at baseline examination (1971-1975) and subsequent development of prostate cancer was examined in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study (1981-1984). The analytic cohort consisted of 2440 men 50 years of age or older who were followed for a median of 10 years. A total of 84 men developed prostate cancer. The mean level of serum vitamin A was significantly lower (P less than 0.01) in prostate cancer cases than in noncases. Considered as a continuous variable or in quartiles, a statistically significant (P less than 0.005 or P less than 0.02, respectively) trend was observed for increased risk of prostate cancer with decreasing levels of serum vitamin A. Adjusted for age and race, men in the lowest quartile had a relative risk of 2.2 (95% confidence intervals, 1.1, 4.3) compared to those in the highest quartile. The elevated risk of prostate cancer associated with the lowest quartile of serum vitamin A levels did not attenuate with increasing time between blood drawing and diagnosis, suggesting that metabolic effects of early disease are an unlikely explanation of these results. The inverse association between serum vitamin A and prostate cancer incidence was independent of age at examination and several other possible confounding variables. This is the first prospective study of serum vitamin A and prostate cancer to include a large (84) number of cases.

Characterizing food intake patterns of American adults.

Food-pattern analysis provides a way to examine diets in a multidimensional context. This study examined the diets of 8181 adults in the 1989-1991 Continuing Survey of Food Intakes by Individuals and evaluated whether they met the federal recommendations for each of five food groups. The sample was partitioned among 32 different food-intake patterns, six of which represented 44% of the population. Nutrient profiles associated with each of the patterns indicated that failure to meet one or more of the food-group recommendations was associated with nutrient inadequacy, macronutrient imbalance, or both. A reexamination of the data to account for low energy reporters did not alter these findings. The pattern of meeting all five of the food-group recommendations was among the least common, accounting for only 1% of adults' intakes.

Evaluation of 2 brief instruments and a food-frequency questionnaire to estimate daily number of servings of fruit and vegetables.

BACKGROUND: Measurement of fruit and vegetable intake is important in the surveillance of populations and in epidemiologic studies that examine the relations between diet and disease. Some situations require the use of brief dietary assessment tools. OBJECTIVE: Our objective was to evaluate the performance of 2 brief dietary assessment instruments, a 7-item standard screener and a new 16-item screener, and a complete food-frequency questionnaire (FFQ) in measuring total fruit and vegetable consumption. DESIGN: About 800 men and women from the National Institutes of Health-AARP Diet and Health Study completed an FFQ, 1 of the 2 screeners, and two 24-h dietary recalls. Fruit and vegetable intakes as measured by each screener and the FFQ were compared with estimated true usual intake by using a measurement-error model. RESULTS: Median daily servings of fruit and vegetables were underestimated by both screeners. The estimated agreement between true intake and the screener was higher for the new screener than for the standard screener and was higher for women than for men. The estimated agreement between true intake and the FFQ was higher than that for both screeners. Attenuation coefficients for the FFQ and screeners were comparable. CONCLUSIONS: For estimating median intakes of fruit and vegetables and the prevalence of recommended intakes being met, the use of screeners without appropriate adjustment is suboptimal. For estimating relative risks in the relations between fruit and vegetable intake and disease, screeners and this FFQ are similar in performance.

Effects of dietary fat and fiber on plasma and urine androgens and estrogens in men: a controlled feeding study.

We conducted a controlled feeding study to evaluate the effects of fat and fiber consumption on plasma and urine sex hormones in men. The study had a crossover design and included 43 healthy men aged 19-56 y. Men were initially randomly assigned to either a low-fat, high-fiber or high-fat, low-fiber diet for 10 wk and after a 2-wk washout period crossed over to the other diet. The energy content of diets was varied to maintain constant body weight but averaged approximately 13.3 MJ (3170 kcal)/d on both diets. The low-fat diet provided 18.8% of energy from fat with a ratio of polyunsaturated to saturated fat (P:S) of 1.3, whereas the high-fat diet provided 41.0% of energy from fat with a P:S of 0.6. Total dietary fiber consumption from the low- and high-fat diets averaged 4.6 and 2.0 g.MJ-1.d-1, respectively. Mean plasma concentrations of total and sex-hormone-binding-globulin (SHBG)-bound testosterone were 13% and 15% higher, respectively, on the high-fat, low-fiber diet and the difference from the low-fat, high-fiber diet was significant for the SHBG-bound fraction (P = 0.04). Men's daily urinary excretion of testosterone also was 13% higher with the high-fat, low-fiber diet than with the low-fat, high-fiber diet (P = 0.01). Conversely, their urinary excretion of estradiol and estrone and their 2-hydroxy metabolites were 12-28% lower with the high-fat, low-fiber diet (P < or = 0.01). Results of this study suggest that diet may alter endogenous sex hormone metabolism in men.

Relation of energy, fat, and fiber intakes to plasma concentrations of estrogens and androgens in premenopausal women.

To evaluate whether diet may influence the incidence of hormone-dependent cancers through an effect on blood estrogen and androgen concentrations, we analyzed diet-blood hormone relations in a cross-sectional study. Dietary energy, fat, and fiber intakes were estimated from 7-d food records completed by 90 premenopausal women on days 14-20 of their menstrual cycles. Fasting blood specimens were collected on days 5-7, 12-15, and 21-23 of each participant's cycle and pooled to create follicular-, midcycle-, and luteal-phase samples, respectively, for analysis. Energy intake was associated inversely with plasma androstenedione and dehydroepiandrosterone sulfate (DHEAS), averaged across the three menstrual cycle phases, and directly with the probability of a luteal-phase rise in progesterone. For each additional 1 MJ (239 kcal) consumed, androstenedione decreased by 6.0% (95% CI: -8.4%, -3.6%), DHEAS decreased by 5.1% (95% CI: -9.6%, -0.4%), and the probability of a progesterone rise increased by 60% (95% CI: 5%, 145%). After energy intake was adjusted for, the ratio of polyunsaturated to saturated fat (P:S) in the diet was significantly inversely associated with plasma estradiol and estrone during the luteal phase of the menstrual cycle. For each 0.1 increment in the P:S, there was a 7.6% (95% CI: -14.3%, -0.5%) decrease in estradiol and a 6.8% (95% CI: -12.7%, -0.6%) decrease in estrone. Results of this cross-sectional study support a relation between both energy and fat ingestion and plasma sex hormone concentrations in premenopausal women.

Assay reproducibility of hormone measurements in postmenopausal women.

As part of a breast cancer case-control study of serum hormones conducted in Columbia, MO, we included several replicate quality control samples to monitor the consistency of laboratory assays. Sera were obtained from three postmenopausal women; from each woman, three samples were placed randomly in each of nine batches with the laboratory unaware of which sample corresponded to whom. Laboratory assays for estrone (E1), estradiol (E2), testosterone, androstenedione (Adione), E1SO4, dehydroepiandrosterone sulfate (DHEAS), follicle-stimulating hormone (FSH), sex hormone binding globulin (SHBG), and percentages of free and albumin-bound E2 were done at a single academic facility. ANOVA results showed that hormone values varied considerably from one batch to the next. The overall coefficients of variation (CVs) estimated for E2, percentage of unbound E2, and percentage of albumin-bound E2 were higher than 15%, but of these, only percentage of unbound E2 had both inter- and intra-assay CVs greater than 10%. Intraclass correlations (ICC) for FSH, SHBG, and DHEAS were high, suggesting that these assays are suitable for population-based studies attempting to link hormone levels to disease risk. The ICC estimated for E1SO4 was quite low due to aberrant values reported in a single batch. For the remaining hormones, the ICCs were fair (ranging from 47% for albumin-bound E2 to 67% for Adione), and studies using these assays would require a substantial increase in the sample size to detect small case-control differences.

Relationship of serum dehydroepiandrosterone (DHEA), DHEA sulfate, and 5-androstene-3 beta, 17 beta-diol to risk of breast cancer in postmenopausal women.

Laboratory evidence suggests a role for dehydroepiandrosterone (DHEA) and its metabolite 5-androstene-3 beta, 17 beta-diol (ADIOL) in mammary tumor growth. Serum DHEA also has been related to breast cancer in postmenopausal women, but the relationship of ADIOL to risk has not been evaluated previously. To assess the relationship of serum DHEA, its sulfate (DHEAS), and ADIOL with breast cancer risk in postmenopausal women, we conducted a prospective nested case-control study using serum from the Columbia, MO Breast Cancer Serum Bank. Cases included 71 healthy postmenopausal volunteers not taking replacement estrogens when they donated blood and who were diagnosed with breast cancer up to 10 years later (median, 2.9 years). Two randomly selected controls, who also were postmenopausal and not taking estrogens, were matched to each case on exact age, date (+/-1 year), and time (+/-2 h) of blood collection. Significant (trend P = 0.02) gradients of increasing risk of breast cancer were observed for increasing concentrations of DHEA and ADIOL, and women whose serum levels of these hormones were in the highest quartiles were at a significantly elevated risk compared to those in the lowest; their risk ratios were 4.0 [95% confidence interval (CI), 1.3-11.8) and 3.0 (95% CI, 1.0-8.6), respectively. The relationship of DHEAS to breast cancer was less consistent, but women whose serum DHEAS concentration was in the highest quartile also exhibited a significantly elevated risk ratio of 2.8 (95% CI, 1.1-7.4). Results of this prospective study support a role for the adrenal androgens, DHEA, DHEAS, and ADIOL, in the etiology of breast cancer.

Relation of prediagnostic serum estrogen and androgen levels to breast cancer risk.

To evaluate the relation of serum sex hormones to breast cancer risk, we conducted a prospective nested case-control study using the Breast Cancer Serum Bank (Columbia, MO). This bank included serum from 3375 postmenopausal women free of cancer and not taking replacement estrogens when they donated blood between 1977 and 1987. Of these, 71 were diagnosed subsequently with breast cancer. For each case, two women alive and free of cancer at the age of the case's diagnosis and matched to the case on age and on date and time of day of blood collection were selected as controls. The median age of subjects at blood collection was 62 years, and the time from blood collection to diagnosis ranged from less than 1 to 9.5 years, with a median of 2.9 years. Postmenopausal women with elevated serum levels of total and non-sex hormone-binding globulin-bound E2 were at an increased risk of developing breast cancer. For non-sex hormone-binding globulin-bound E2, risks were elevated 4-5 fold for women in the upper three quartiles relative to those in the lowest quartile. Although breast cancer was not related to estrone or estrone sulfate concentration, the ratio of estrone sulfate to estrone was significantly inversely associated with risk, suggesting that women who develop breast cancer may be less able to metabolize estrone to its less active form. Serum testosterone was significantly positively associated with postmenopausal breast cancer; the relative risk for women in the highest versus the lowest quartile was 6.2 (95% confidence interval, 2.0-19.0). Our results support the hypothesis that prediagnostic serum estrogens and androgens are related to the subsequent diagnosis of breast cancer in postmenopausal women.

Relationships of age and reproductive characteristics with plasma estrogens and androgens in premenopausal women.

We used data from a cross-sectional study of 107 premenopausal women to evaluate the relation of age, menarcheal age, parity, and age at first live birth with plasma estrogen and androgen levels in premenopausal women. Fasting blood specimens were collected on each of days 5-7, 12-15, and 21-23 of menstrual cycles of the participants and pooled to create follicular, midcycle, and luteal phase samples, respectively, for each woman. Age was associated significantly and positively with plasma estradiol levels during the follicular phase [percentage difference/year = 2.6; 95% confidence interval (CI) = 1.0-4.2] and midcycle (percentage difference/year = 2.7; 95% CI = 0.9-4.7) but not the luteal phase (percentage difference/year = -0.4; 95% CI = -1.9-1.3) of the menstrual cycle. The relation of age to plasma estradiol varied by parity, with significant interactions during midcycle and luteal phase. Among nulliparous women, plasma estradiol levels increased with age midcycle and during the luteal phase, but among parous women estradiol levels decreased with age during these phases of the menstrual cycle. Plasma estrone increased with age in all women during the follicular phase of the menstrual cycle (percentage difference/year = 1.5; 95% CI = 0.2-2.8). During the luteal phase there was a significant interaction with parity; estrone levels in nulliparous women varied only slightly with age, but levels in parous women decreased significantly as age increased. The androgens, androstenedione and dehydroepiandrosterone sulfate decreased, and sex hormone-binding globulin increased as age increased. The results of this cross-sectional study suggest that pregnancy may modify age-related changes in plasma estrogen levels.

Dietary sources of nutrients among US children, 1989-1991.

OBJECTIVE: To identify major food sources of nutrients and dietary constituents for US children. METHODS: Twenty-four-hour dietary recalls were collected from a nationally representative sample of children age 2 to 18 years (n = 4008) from the US Department of Agriculture's 1989-1991 Continuing Survey of Food Intakes by Individuals. For each of 16 dietary constituents, the contribution of each of 113 food groups was obtained by summing the amount provided by the food group for all individuals and dividing by total intake from all food groups for all individuals. RESULTS: Milk, yeast bread, cakes/cookies/quick breads/donuts, beef, and cheese are among the top 10 sources of energy, fat, and protein. Many of the top 10 sources of carbohydrate (yeast bread, soft drinks/sodas, milk, ready-to-eat cereal, cakes/cookies/quick breads/donuts, sugars/syrups/jams, fruit drinks, pasta, white potatoes); protein (poultry, ready-to-eat cereal, pasta); and fat (potato chips/corn chips/popcorn) also contributed >2% each to energy intakes. Ready-to-eat cereal is among the top contributors to folate, vitamin A, vitamin C, iron, and zinc intakes. Fruit drinks, containing little juice, contribute approximately 14% of total vitamin C intakes. CONCLUSIONS: Fortified foods are influential contributors to many vitamins and minerals. Low nutrient-dense foods are major contributors to energy, fats, and carbohydrate. This compromises intakes of more nutritious foods and may impede compliance with current dietary guidance.

Serum sex hormone levels are related to breast cancer risk in postmenopausal women.

We conducted a nested case-control study to prospectively evaluate the relationship of serum estrogens and androgens to risk of breast cancer in postmenopausal women. From 1977 to 1987, 3375 postmenopausal women free of cancer and not taking replacement estrogens donated blood to the Breast Cancer Serum Bank in Columbia, Missouri. Of these, 72 were subsequently diagnosed with breast cancer. For each case, two controls matched on age and date and time of day of blood collection were selected using incidence density matching. The median age of subjects at blood collection was 62 years; the time from blood collection to diagnosis ranged from less than 1 to 9.5 years with a median of 2.9 years. Risk of breast cancer was positively and significantly associated with serum levels of estrogens and androgens. Compared to women in the lowest quartile, those in the highest quartile for non-sex hormone-binding globulin (non-SHBG) bound (bioavailable) estradiol had a relative risk of 5.2 (95% confidence interval [CI] = 1.5-18.5) and those in the highest quartile for testosterone had a relative risk of 6.2 (95% CI = 2.0-19.0). Our results lend considerable support to the hypothesis that serum concentrations of estrogens and androgens are related to the subsequent diagnosis of breast cancer in postmenopausal women.

Antithrombin III metabolism in patients with liver disease.

Liver diseases are associated with complex haemostasis defects, in which platelets, coagulation, and fibrinolysis may all be affected. The low plasma concentrations of clotting factors often found can be the result of many changes such as impaired synthesis, increased catabolism due to intravascular coagulation, or alternate distribution. In this study, we investigated the metabolism of purified human antithrombin III(AT III) labelled with 125I in 25 patients with histologically established liver disease and in nine control subjects. The results showed that, in general, low plasma concentrations of AT III in liver cirrhosis are not due to consumption in the central compartment but rather to altered transcapillary flux ratio. Such altered transcapillary flux ratios may already exist even with normal plasma AT III concentrations. Altered ratios are not only found for coagulation proteins but also for albumin and thus may be a general phenomenon of liver disease. In micronodular cirrhosis the alpha phase, the transcapillary efflux (k1, 2) and influx (k2, 1) were significantly increased compared with the normal subjects.

Fruit and vegetable intakes of children and adolescents in the United States.

OBJECTIVES: To identify the ways in which fruits and vegetables are consumed by children, to provide estimates of their intakes compared with recommendations, and to estimate the percentage of children meeting those recommendations. DESIGN: We examined 3 days of dietary data from respondents in the US Department of Agriculture's 1989-1991 Continuing Survey of Food Intakes by Individuals. All foods reported in the survey were disaggregated into their component ingredients; all fruit and vegetable ingredients were assigned specific weights to correspond with a serving as defined by current dietary guidance materials; and the number of servings of each fruit and vegetable was tallied. PARTICIPANTS: A total of 3148 children and adolescents aged 2 to 18 years in the 48 conterminous United States. MAIN OUTCOME MEASURES: Percentages of fruit and vegetable servings consumed in various forms, mean number of servings consumed per day, and percentage of persons meeting various recommendations by sex/age, race/ethnicity, and household income. RESULTS: Nearly one quarter of all vegetables consumed by children and adolescents were french fries. Their intakes of all fruits and of dark green and/or deep yellow vegetables were very low compared with recommendations. Only one in five children consumed five or more servings of fruits and vegetables per day. CONCLUSION: Pediatricians should encourage the consumption of fruits and vegetables, especially dark green and deep yellow vegetables, by children.

Rapid microanalysis of coagulation parameters by automated chromogenic substrated methods - application in neonatal patients.

Daily monitoring of coagulation parameters in critically ill premature born neonates is only possible on small amounts of blood obtained by heelpuncture. Therefore, automated spectrophotometric micro-assays for antithrombin III (AT III), factors II and X, plasminogen and alpha 2 antiplasmin were applied on capillary and venous blood samples concurrently obtained in adults and healthy neonates. No statistically significant difference for any of the parameters was revealed. High levels of platelet factor 4 present in serial capillary samples of adults, did not interfere with the heparin dependent AT III assay. There was no evidence of thrombin or thromboplastin generation in these capillary samples, when examined for Va or VII activities. The levels of AT III, factors II and X and of plasminogen in neonates were 35-45% of the adult levels, in contrast to alpha 2 antiplasmin which was in the adult range.

Antithrombin III in normal pregnancy.

Plasma antithrombin III (AT III) was determined in 94 women during and after normal pregnancy employing an automated amidolytic technique. The patients were selected on the following criteria: no toxaemia, spontaneous delivery at term, birth-weight above the 10th percentile and discharged with a healthy baby. AT III levels during pregnancy and early puerperium were not lower than own control values obtained 6-8 weeks after delivery.

Quantitative endotoxin determination in blood with a chromogenic substrate.

A method is described for the quantitative determination of endotoxins in blood. The method is based upon the endotoxin-dependent activation of a proenzyme present in Limulus amebocyte lysate. This activated enzyme is measured by using the chromogenic substrate S 2422. Inhibitors and activated coagulation factors possibly interfering in the assay are removed by dilution and boiling. The method has been proven to be fast (2.5 h), sensitive and reproducible with a detection limit of 10 ng/l. Preliminary results comparing the results of blood cultures with the endotoxin assay indicate a good correlation.