The changing face of pathology--an Australian perspective.

Despite Government at various levels in Australia attempting to force restraint by limiting financial resources, modern medicine and community expectations will continue to place demands on health services. The principal illnesses confronting society are unlikely to change, with conditions such as cancer, cardiovascular disease and diabetes remaining at their current prevalence. Early and more sophisticated detection and monitoring of these diseases will be required, with concomitant increases in costs. Overriding this in Australia is the increase in the age of the population, which will also have a major impact on health costs. This article examines the effect, on pathology services, of changes occurring within the health system in Australia, especially the impact on public hospital pathology.

The effect of removal of profile requesting on chemical pathology requesting patterns.

We investigated the effect on pathology requesting behaviour in a metropolitan teaching hospital, following the proscription by the Health Insurance Commission of the MBA (multiple biochemical analysis) request. Our laboratory had provided a 20 test profile in response to a request for MBA until February 1991, when the MBA request was no longer accepted. During the period February to June 1991, requesting clinicians had to comply with the new requesting requirements, although they continued to receive the results of the 20 test profile because of limitations imposed by our laboratory instrumentation. After June 1991, with the installation of a new analyzer that allowed discretionary requesting, results were provided only for those tests requested. We studied requesting patterns in the 3 time periods: i.e. (1) before the MBA request was withdrawn, and after the MBA request was withdrawn, (2) firstly while results for the 20 test profile were still provided and (3) secondly when the results were provided only for the tests requested. For each of the 3 periods the average number of requests per day for MBA, group and individual tests was calculated. The effect of removal of the MBA request on the Medicare Benefits payable was estimated. We found compliance by the requesting clinicians with the new requirements and a reduction in the number of tests requested. There was a reduction from 20 to 12 in the average number of tests per request. This was associated with a 2.2% reduction in the Medicare Benefits payable.

Biochemical markers of acute myocardial infarction: strategies for improving their clinical usefulness.

We investigated the early diagnostic utility, including incremental value, of the serum cardiac markers creatine kinase (CK), CK-MB (mass and activity measurements), cardiac troponin T, and myoglobin in the diagnosis of acute myocardial infarction (AMI) in patients presenting to a major teaching hospital with chest pain and non-diagnostic electrocardiographs (ECG). The reference diagnosis of acute myocardial infarction was made by a single, independent cardiologist using World Health Organization criteria. CK and CK-MB mass were the only significant predictors of AMI at presentation to the Emergency Department. Logistic regression analysis revealed that CK did not significantly predict (P = 0.23) myocardial infarction once CK-MB mass was in the model. Using test results on follow up, in addition to presentation CK-MB mass, change in CK-MB mass was the only other significant independent predictor of AMI. Likelihood ratios for various levels of the significant markers in the logistic regression are given. In conclusion, CK-MB mass measurement was the only useful serum cardiac marker for the diagnosis of AMI in patients presenting with chest pain with non-diagnostic ECGs.

An evaluation of osmolality measurement by freezing point depression using micro-amounts of sample.

An evaluation of the Advanced micro-osmometer is presented. This instrument has been shown to have an excellent analytical precision (within-run CV = 0.59%, between-day CV = 0.58%). It is accurate over an analytical range of 0-2000 mmol/kg of osmolality shown by linearity studies and split sample correlations against vapour pressure osmometry, freezing point osmometry and an external quality assurance programme. Analytical errors due to operator technique are almost eliminated because of good instrument design. Preliminary results on whole-blood osmolality are included. The required sample size of 20 mul permits osmolality measurements on most clinical samples. It is concluded that the Advanced micro-osmometer satisfies laboratory requirements.

The pathogenesis of idiopathic hypercalciuria: evidence for parathyroid hyperfunction.

We studied the effect of calcium deprivation and loading in 17 healthy subjects and 76 patients with renal calculi. Five had primary hyperparathyroidism with an elevated plasma ionised calcium and detectable plasma parathyroid hormone. Forty-nine had idiopathic hypercalciuria, defined by a urine calcium greater than 7 mmol/day on a free diet. Twenty-two were normocalciuric. Fasting plasma calcium, corrected for albumin, was higher in the patients with idiopathic hypercalciuria (2.40 +/- 0.10 mmol/l) than in controls (2.28 +/- 0.05 mmol/l, p less than 0.005). Plasma calcium was intermediate in the normocalciuric stone formers (2.35 +/- 0.08 mmol/l) and elevated in the patients with primary hyperparathyroidism (2.62 +/- 0.07 mmol/l). Nephrogenous cyclic adenosine monophosphate (cAMP) and parathyroid hormone levels were highest in the primary hyperparathyroid group and did not differ significantly within the other groups. Nephrogenous cAMP correlated positively with plasma calcium in the patients with primary hyperparathyroidism and negatively in controls; there was no correlation in the idiopathic hypercalciuria group. Following an oral calcium load, plasma calcium rose and nephrogenous cAMP fell similarly in all groups. Fasting urinary calcium and its increase after load were greatest in the idiopathic hypercalciuria and primary hyperparathyroid groups, with intermediate results in the normocalciuric patients. Neither the initial metabolic patterns nor the response to thiazide fitted with the previously described patterns of absorptive and renal hypercalciuria. Increased parathyroid gland activity is the most probable cause of idiopathic hypercalciuria.

Diet modification in lowering plasma cholesterol levels. A randomised trial of three types of intervention.

OBJECTIVE: To compare the efficacy of three types of diet and lifestyle interventions for lowering plasma lipid levels. DESIGN: Randomised parallel-group trial. SUBJECTS AND SETTING: Adults with plasma cholesterol levels of 5.5-8.0 mmol/L attending two Sydney community health screening clinics were asked to participate: 179 agreed and 131 completed the study. INTERVENTIONS: A pamphlet with brief advice; group dietary counselling; or individual counselling. Counselling included three sessions with a dietitian/nutritionist over six months. MAIN OUTCOME MEASURES: Plasma total cholesterol levels measured by Reflotron analyser; fasting serum lipid levels measured by standard laboratory methods; and calculated low-density lipoprotein cholesterol levels. RESULTS: Significantly lower plasma total cholesterol levels (Reflotron) were observed at two months and at six months with each of the three interventions. Additionally, both types of dietitian-based counselling resulted in small but significant decreases in plasma low-density lipoprotein cholesterol levels at six months in a subset of subjects. CONCLUSION: Although there were no statistically significant differences in efficacy between the three types of intervention, dietitians have a role to play in setting up such counselling programs.

Assessment of physicians' office pathology testing: organisational considerations.

In this paper we consider organizational and design aspects of an assessment of physicians' office pathology testing, and discuss difficulties in measuring the level of performance and effectiveness of such diagnostic services. A major consideration is the trade-off between compliance with a well-defined protocol, and use of the technology in a way which resembles normal operating practice.