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Biomedical subjects

P M Broughton

Publications and source records attributed to P M Broughton.

At least 19 recordsLinked to original sources
PubMed1994

The assessment of biological age: a report from the Department of Environment Study.

Indicators of ageing were measured in 397 male and 130 female London Civil Servants aged from 37 to 58 years of age. Grey hair, skin inelasticity, and arcus senilis were strongly and independently related to chronological age. Also independently related were serum albumin (negatively related in both sexes), baldness, serum creatinine, systolic blood pressure, serum calcium (negatively) and ESR in men, and serum cholesterol in women. Chronological age was regressed on the above variables for men and women separately to provide regression equations. Biological age for an individual was calculated by entering his or her results and calculating the residuals. Biological age in those who stopped smoking tended to be younger than chronological age by an average of 12-13 months in men and 1-4 months in women. Men and women who had never smoked had higher biological than actual ages but not after adjusting for regression dilution bias. Men who currently smoked had higher biological ages of 2-3 months but not women smokers (4-6 months lower). Similarly, men of lower employment grades had an average biological age 13 months older and women 8 months, compared with higher employment grades. These differences between employment grade appeared to be due to ESR, arcus senilis, systolic blood pressure and serum cholesterol. These four measurements may be markers of biological rather than chronological age, and the value of attempting to measure biological age is discussed.

Adult↗
PubMed1994

Age differences in biochemical and hematological measures during middle age.

Biochemical and hematological measures possibly associated with ageing were measured on a single occasion in 3402 male and 2152 female London Civil Servants aged from 35 to 59 years of age. These included erythrocyte sedimentation rate (ESR), blood hemoglobin and serum albumin, calcium, bilirubin, creatinine, urea, urate, high density lipoprotein (HDL), and total cholesterol. Independently and positively related to age were ESR with an estimated 47% 'increase' in men over the 15 years between ages 40 to 55 and a 40% increase in women; serum urea had a 6%/15-year increase in men and 20% in women; total cholesterol had a 6%/15-year increase in men and 18% in women; serum creatinine 'increased' by 2%/15-years in men and 5% in women. In women, urate, HDL cholesterol and hemoglobin increased with age group. Negatively related to age was serum bilirubin in both sexes (8% and 6% 'fall'/15-years in men and women respectively). Serum albumin and calcium fell with age group in men. The sexes differed in their relationship to aging for total cholesterol and HDL cholesterol (greater increase in women), serum calcium (small decrease in men and small increase in women), urate and hemoglobin (increases in women but not men). Urea increased more in women than men, and albumin decreased more in men than women (p < 0.001 for all comparisons with the exception of HDL cholesterol, p < 0.01). Changes during the menopause were thought to explain some of these findings.

Adult↗
PubMed1993

The role of expert systems in improving the test requesting patterns of clinicians.

The many strategies proposed for influencing the test requesting patterns of clinicians have had only limited success, largely because they are labour intensive and depend on motivation and commitment. Clinical protocols which have been locally agreed between laboratory staff and clinicians are potentially one of the more successful strategies, but detailed study of their application in different clinical settings has been limited by practical problems. Expert systems offer a way of implementing locally agreed protocols and, consequently, of assisting the identification, audit and refinement of laboratory testing strategies. Where these systems have been applied in specialist units they have resulted in savings in time by both clinical and laboratory staff, and an overall reduction in the number of clinical chemistry tests done within and out of hours. These systems offer promise as a method of improving laboratory utilization.

Clinical Laboratory Information Systems↗
PubMed1992

Modifying the request behaviour of clinicians.

AIM: To evaluate whether the feedback of laboratory use and cost data to clinicians modifies their request behaviour. METHODS: Over two years the effect of monthly feedback of clinical chemistry test use and revenue expenditure to three consultant physicians on their clinical chemistry and haematology requesting patterns was evaluated. Two physicians who received no information served as controls. RESULTS: Feedback over one year led to an immediate and sustained decrease of 15%, 27%, and 21% in clinical chemistry requests (p less than 0.01), tests (p less than 0.001), and revenue expenditure (p less than 0.001), respectively, and a 10% reduction in haematology tests (p less than 0.05) per outpatient visit. These changes persisted in the six months after the feedback was stopped. CONCLUSIONS: These results suggest that feedback of laboratory data to clinicians modifies their request behaviour and that supplying clinicians with information on what they do can influence the way they make decisions.

Clinical Laboratory Techniques↗
PubMed1992

Comparison of the use of four desktop analysers in six urban general practices.

There is little data on the advantages and disadvantages of using desktop analysers in general practice. This prospective trial compared four of the analysers available in the United Kingdom, in six urban general practices, over a six month period. Of the 2619 tests where the time was noted, 55.8% were performed outside the hours when routine transport to a hospital laboratory was possible (after 12.00 hours). Of the 3530 tests performed the commonest were measurements of cholesterol (14.4 tests per 5000 patients per 30 days), glucose (6.0 tests) and haemoglobin (5.6 tests). Less than 5% of the tests were performed as an emergency despite the speed at which results are available. The main reasons for requesting the tests were screening or case finding (56.9%), with the remainder for monitoring chronic disease, especially diabetes and hypercholesterolaemia. There was evidence that the use of the machines in the four practices reduced requests for hospital laboratory blood tests by 24-40% of pre-study levels. However, there was a considerable increase in testing for cholesterol (three fold) and haemoglobin (eight fold) on the desktop analysers, compared with the number of laboratory tests requested before the study. The cost per test of using such machines is closely related to the level of activity and probably does not compete favourably with hospital testing unless several tests are performed each day. Quality control tests were within the specified limits on at least 98% of occasions, however these tests also identified the need for laboratory back up where a problem was found.

Blood Chemical Analysis↗
PubMed1991

The assessment of the relationship between blood pressure and sodium intake using whole-day, daytime and overnight urine collections.

The usefulness of whole-day, daytime (waking to retiring time) and overnight urine samples for assessing the relationship between blood pressure and sodium intake was examined in 301 male London civil servants, aged from 37 to 58 years old. Systolic blood pressure (SBP)/diastolic blood pressure (DBP) averaged 126/78 mmHg and the 24-h urinary excretion of sodium and potassium was 174 and 73 mmol, respectively. There was poor consistency between day- and night-time urine samples with respect to both sodium and potassium content. The urinary excretion of sodium and potassium was lower (P less than 0.001) in overnight than in daytime samples. After standardization for creatinine, the night: day ratio was 0.79 for sodium output and 0.55 for potassium excretion. Blood pressure, adjusted for age and body mass index, was significantly and positively correlated with overnight sodium excretion (SBP/DBP: slope = 0.061/0.046 mmHg/mmol) whereas the correlations with sodium excretion in daytime (0.010/0.004 mmHg/mmol) and whole-day (0.024/0.016 mmHg/mmol) urine samples were not significant. Blood pressure was significantly correlated with the sodium:potassium ratio in whole-day urine (1.941/1.968 mmHg/unit). As the agreement between daytime and overnight urine samples was low with respect to both sodium and potassium content, and due to the fact that the relationship between blood pressure and sodium in overnight samples may at least partially reflect pressure diuresis, overnight urinary sodium, even if related to sodium intake, cannot be employed to assess the association between salt in the diet and blood pressure.

Adult↗
PubMed1991

Feedback of laboratory usage and cost data to clinicians: does it alter requesting behaviour?

In a 1 year prospective study we evaluated the effect of feedback of laboratory data on the requesting behaviour of physicians in general medicine. Data on within-hours and out-of-hours clinical chemistry laboratory usage and revenue expenditure for inpatients and outpatients, expressed in terms of clinical workload, were supplied monthly to a group of three consultant physicians in general medicine. With these data the physician could monitor his performance over a period of time and compare it with that of his peers. Two consultants in general medicine who received no information served as controls. Over a period of 6 months, there was a 25%, 13% and 18% decrease in tests (P less than 0.01), requests (P less than 0.05) and revenue expenditure (P less than 0.01) per outpatient visit, respectively, in the intervention group of physicians following the introduction of feedback when compared to their baseline period and to the control group. The decrease (P less than 0.01) was in the commonly requested and 'seemingly cheap' tests. There was no significant change in laboratory use and expenditure on inpatients. The feedback of laboratory data was acceptable to the physicians, raised their awareness of laboratory usage and costs and decreased laboratory workload and expenditure.

Feedback↗
PubMed1990

Improving the quality of plasma cholesterol measurements in primary care.

During the last 2 years an external quality assessment (EQA) scheme has been developed for plasma cholesterol measurements made in primary care. The scheme, which is supported by the UK Department of Health and by the instrument manufacturers, now has over 300 participants, most of whom use the Boehringer Reflotron. Operators are mostly nurses, with little or no laboratory experience. To avoid matrix effects, fresh plasma specimens collected from normal volunteers and those attending a hospital lipid clinic are used. Three specimens, mostly with cholesterol concentrations in the range 5-9 mmol/L, are distributed every 2 months. The mean plasma cholesterol results show good agreement with those from 'reference' laboratories, and efforts are now being made to link these laboratories with the CDC-based reference system. The scheme uses a predominantly graphical presentation of results, with a greater element of interpretation by the organisers than is usually provided for laboratory-based participants. The distribution of results shows a higher proportion of outliers than in the UK national EQA scheme for laboratory cholesterol measurements. At present about 10% of participants in primary care obtain results which could be clinically misleading, and new approaches are needed in dealing with these 'poor performers'. This scheme could serve as a model for other assays in primary care. It illustrates the importance of training, quality assurance and education, and the need for laboratory staff to become more involved in this growing and important area of laboratory medicine.

Chemistry, Clinical↗
PubMed1990

Laboratory testing in, or for, general practice.

Recent technological advances make it possible for general practitioners to do many laboratory tests in the doctor's office. This has advantages and limitations, and a new balance must be found between testing within and outside laboratories. General practitioners will need to decide which tests to do within the practice, and laboratory staff have opportunities to become more involved in the needs and problems of general practice, so that they are able to advise on when and how tests are best performed.

England↗
PubMed1989

Quality of plasma cholesterol measurements in primary care.

Three surveys were made of the quality of plasma cholesterol measurements performed with a commercial desktop analyser (BCL Reflotron) in primary care. Each survey included three specimens, and results were received from 37, 61, and 69 participants. Although many participants obtained satisfactory results, 8.6% of the results differed by 1.0 mmol/l or more from the target values, and the overall between instrument dispersion of results was 1.3 times that between hospital laboratories. It was found that common sources of error were poor technique and the use of outdated reagent strips. Users of such instruments outside the laboratory need help and advice with training, and guidelines for this are provided. The main recommendations are that users should establish contact with a local clinical chemistry laboratory for training and support and should participate in external quality assessment schemes.

Cholesterol↗
PubMed1989

Diurnal variations in serum biochemical and haematological measurements.

Twenty five biochemical and haematological measurements were determined on nonfasting blood and serum samples collected between 9 am and 7 pm from a representative group of 7685 British middle-aged men. Most measurements showed significant diurnal variations, but only for bilirubin, phosphate, and triglyceride did time of day account for more than 5% of the between subject variance. Serum bilirubin concentrations showed a pronounced downward trend in the afternoon, the mean value after 6 pm being 30% lower than the mean value in the morning. Mean serum triglyceride and phosphate concentrations increased steadily through the day. Mean concentrations of potassium, haemoglobin, and haematocrit and red cell count were higher in the morning, while urea and creatinine concentrations and white cell count had higher means in the afternoon. Glucose showed a pattern consistent with short term response to meals. The effects of these diurnal trends on routine use of biochemical tests needs careful consideration, and a greater understanding of their biological mechanisms is required.

Adult↗
PubMed1989

Laboratories respond differently to the same clinical request.

A survey of 19 clinical chemical laboratories, undertaken to determine what tests would normally be done in response to a number of common clinical requests (e.g. 'plasma electrolytes please'), revealed wide variations in test patterns. It is suggested that laboratories must bear some of the responsibility for unnecessary testing, and that new strategies are needed to persuade laboratories to adopt more cost-effective test patterns.

Adult↗
PubMed1987

Performance requirements of tests performed nearer the patient.

Commercial test systems which can be used outside the laboratory are proliferating, but there are doubts about the quality of results obtained when they are used by unskilled staff. Although rapid but approximate results can be invaluable in some clinical situations, they can be disastrous in others, particularly when the results conflict with those obtained by conventional laboratory techniques. The clinician needs to define his requirements for the quality of such tests, and the manufacturer encouraged to produce equipment which gives accurate results, independent of the skill of the operator. The laboratory scientist has an important role in the development and effective application of tests performed nearer the patient.

Clinical Laboratory Techniques↗