Nils Tryding

Cholestasis of Pregnancy: Clinical and Laboratory Studies

A prospective study was made of clinical symptoms, liver function and pregnancy prognosis in women with cholestasis of pregnancy (CP). We used several positive and negative criteria to allow a clinical definition of CP as itching limited to time of pregnancy with or without laboratory evidence of liver dysfunction. the incidence during 1971–74 was 1.5% (100/6798 women) and lower during 1980–82 (52/5 441 = 1.0%). One hundred consecutive pregnant women without itching were used as clinical controls. the incidence of CP showed a distinct seasonal variation, culminating in November. Women with CP had often had itching during previous pregnancies and during use of contraceptive pills and described anamnestically itching in mother and sisters. Laboratory data in CP were compared with reference intervals for healthy pregnant women. Serum enzyme levels were significantly increased for serum alkaline phosphatase, 5‐nucleotidase, aspartate aminotrans‐ferase and alanine aminotransferase in the second and especially in the third trimester. the enzyme distribution was often markedly skewed to the right, i.e. some patients reacted more than others. Most patients with cholestasis only had itching without pronounced abnormalities in laboratory data. This mild form of CP was associated with a good prognosis for both mother and child.

Towards common reference intervals in clinical chemistry. An attempt at harmonization between three hospital laboratories in Skåne, Sweden.

Abstract The population sample of the Kristianstad survey, a reference intervals survey in the county of Kristanstad, was used to establish new reference intervals in clinical chemistry at the laboratories of the Central Hospital in Kristianstad, the University Hospital in Lund and the University Hospital in Malmö. Three-hundred and fifty nine subjects, male and female, aged 20–80+ years, were invited to participate in the study, with a participation rate of 70 %. Up to 70 analyses were performed on each subject, general clinical chemistry parameters in all three laboratories, specialized analyses where available. Separate a priori exclusion criteria were defined for each test. In addition, the test pattern of each individual was evaluated for signs of preclinical disease. Twelve cases of preclinical disease were discovered and clinically confirmed. Details on all test methods are presented along with information concerning instruments used, calibration procedures, methods of calculation and obtained reference intervals. Although the methods were in general calibrated against acknowledged reference materials, in some instances differences were found that made common reference intervals across all laboratories impossible. Problems relating to the practical use of international recommendations and the establishment of reliable reference intervals are discussed.

Large differences in laboratory utilisation between hospitals in Sweden.

Abstract There are large differences in the use of laboratory tests between hospitals in Sweden. These differences are not only due to differences between the patients treated but also to differences in practice. Use of laboratory test seems to reflect local traditions to a large extent. These large variations in practice are not compatible with the objective of providing care on equal terms and reduce the cost-effectiveness of clinical chemistry. Recently, several intervention studies have been performed in Sweden with the aim to optimise the use of clinical chemistry tests in primary care. The results show that it is possible to reduce the cost in primary care by SEK 100 million per year while increasing the clinical usefulness. This constitutes approximately 10% of the total cost for clinical chemistry tests in primary care. It should also be possible to reduce the cost for clinical chemistry tests in secondary and tertiary care. Hospitals order more tests than primary care and the potential savings are thus greater. We have studied the ordering habits for eleven Swedish hospitals. The comparison was made in the form of ratios between related laboratory tests to reduce the effects of differences in size between the studied laboratories. The large variation between hospitals indicates that a continuous discussion between the clinicians and the laboratories could reduce the cost. We have used the figures from the comparison and calculated the potential savings for seven frequently used tests. The potential yearly saving in Sweden for these tests is approximately SEK 150 million.

DDAVP test for renal concentration capacity. Age-related reference intervals.

The effect of different levels of fluid intake on the renal concentration test was evaluated. Maximal urinary osmolality did not significantly differ whether strict fluid restriction was kept or not. One side effect, namely headache, seemed more frequent after fluid deprivation than after a more liberal fluid intake. We suggest a practical approach to the performance of the urinary concentration test with DDAVP. The maximal urinary concentration after a single subcutaneous injection of 4 micrograms DDAVP was determined in 212 healthy adults aged 20 to 80 years. A significant decline with age was found in maximum urinary concentration, mean values ranging from 982 mOsm/kg at 20 years to 823 mOsm/kg at 80 years. References are given for different ages which render the test useful in adult patients.

EFFECT OF PHENYTOIN ON THE TRYPTOPHAN LOAD TEST

Tryptophan load tests were performed on 51 children, including 27 with epilepsy. In controls and in patients not receiving phenytoin the xanthurenic acid excretion in urine increased with age. No difference was found between the mean values for controls, non‐epileptic patients with neurological diseases and epileptic children not receiving hydantoin derivatives. In epileptic children treated with phenytoin the excretion of xanthurenic acid was higher than in the other 3 groups. The xanthurenic acid excretion increased in healthy children given phenytoin 10 mg/kg/day for at least 5 days. The mean difference between the results of the tryptophan load test before and during phenytoin administration in 8 epileptic children and 5 healthy controls was significant. In all but one of these children xanthurenic aciduria increased during administration of phenytoin. In none of the few patients who showed a clinical response on pyridoxine (100–150 mg/ day) was the tryptophan load test abnormal before treatment with pyridoxine.

Reference Values for Serum Components in Pregnant Women

Abstract. Reference values have been collected for 11 chemical blood serum components during the three trimesters of pregnancy in 100 healthy pregnant women. The results used for reference intervals are presented as 2.5, 50 and 97.5 percentiles. Especially regarding S‐Albumin, S‐Alkaline phosphatase and S‐5′‐Nucleotidase the changes were most pronounced during the third trimester. S‐Gammaglutamyltransferase did not change significantly during pregnancy. For S‐Aspartate aminotransferase and S‐Alanine aminotransferase there were no significant changes in the mean values during the three different trimester periods. In the third trimester the frequency distribution of the enzymes became skewed to the right, i.e. in some women the enzyme activities increased noticeably more than in others. S‐Na showed a significant decrease even during the first trimester and this lowering was slightly more pronounced during the second and third trimesters. S‐Ca decreased in parallel with S‐Albumin concentration. The changes in S‐CaAlbumincorrected were distinctly smaller than those in S‐CaTotal. Throughout pregnancy, S‐K, S‐Bilirubin and S‐Thymol turbitidy test values did not deviate from nonpregnant levels.