Intra-individual variation of analytes in serum from patients with chronic liver diseases

The average biological intra-individual CV in 20 patients with chronic liver diseases (CLD), estimated for 14 analytes during a stationary phase, significantly exceeded that for a normal group in the cases of Na+, K+, Cl-, total protein, albumin, cholinesterase, hemoglobin, and alpha-amylase; it did not differ significantly from the normal group for cholesterol, alkaline phosphatase, aspartate aminotransferase, and alanine aminopeptidase; and it was significantly lower than in the normal group for alanine aminotransferase and gamma-glutamyltransferase. There were no significant sex-related differences in mean intra-individual variation in CLD patients. Individual values were gaussian-distributed for all analytes, including enzymes. The estimated biological component of intra-individual variation and the analytical variation as determined for each laboratory can be used to derive decision-making criteria in monitoring CLD.     

Intra-individual variation of some analytes in serum of patients with insulin-dependent diabetes mellitus

Biological intra-individual variation in concentrations of 16 clinical biochemical analytes in serum was estimated for 27 patients with insulin-dependent diabetes mellitus (IDDM), and results were compared with those for apparently healthy individuals. In general, the variation was significantly higher in the patients. The ratio of the average intra-individual variation in IDDM patients to that in normal subjects exceeded 2.0 for Na+, K+, creatinine, and alpha-amylase; 1.50 to 2.0 for Cl-, total protein, albumin, cholesterol, and hemoglobin; and 1.2 to 1.5 for urea, uric acid, high-density-lipoprotein cholesterol, and aspartate aminotransferase. This increased variability in IDDM patients may be caused by variations in osmotic diuresis. Average intra-individual variations were greater for women than for men for Na+, total protein, albumin, and hemoglobin. Individual values showed a gaussian distribution for all analytes, including enzymes and triglycerides. No intra-individual variation was time dependent. For practical purposes, decision-making criteria in monitoring IDDM can be derived from the estimated biological component of intra-individual variation and the analytical variation established for each laboratory.     

New automated measurement of mitochondrial aspartate aminotransferase with use of protease 401

Total mitochondrial aspartate aminotransferase (EC 2.6.1.1), the sum of apo- and holo-mitochondrial aspartate aminotransferase activity in human serum, was measured by using a proteolytic method: inactivation of cytosolic aspartate aminotransferase with cytosolic aspartate aminotransferase-inactivating protease 401 from Streptomyces violaceochromogenes. Cytosolic aspartate aminotransferase is completely inactivated, and apo-mitochondrial aspartate aminotransferase is completely activated by pyridoxal 5'-phosphate within 5 min. Results by the proposed method correlated well with those by an immunochemical method (r = 0.994, n = 145) and showed excellent inhibitory activity of the protease for holo- and apo-cytosolic aspartate aminotransferase up to 5000 U/L and activation of mitochondrial apo-aspartate aminotransferase up to 2000 U/L in the presence of 100 mumol of pyridoxal 5'-phosphate per liter. Within-run Cvs were good (1.13-7.49%). Mean values for total mitochondrial aspartate aminotransferase and apo-mitochondrial aspartate aminotransferase activities in serum of the healthy subjects were 4.8 (SD 0.9) and 1.8 (SD 0.8) U/L, respectively (n = 154). Various common interferents tested did not affect this assay.     

Pediatric reference intervals for 19 biologic variables in healthy children

We defined age- and sex-specific reference intervals for 19 biologic variables in serum samples from healthy children, 1 to 22 years of age, using common laboratory equipment. Upper and lower reference intervals were defined as the estimated 2.5 and 97.5 percentiles of the distribution. For variables (y) that varied with age, the relationship of y to age was modeled with polynomial regression. Parametric percentile estimates specific to each age were then calculated as the predicted y value +/- 1.96 . SD, in which SD = the standard deviation of the residuals. For variables not associated with age, the nonparametric 2.5 and 97.5 sample percentiles were used to define the reference intervals. No significant age or sex differences were found for serum sodium, total protein, glucose, direct bilirubin, or albumin. Potassium, chloride, and urea showed constant values in children that were higher than adult values in the case of potassium and chloride and lower than adult values in the case of urea. No sex-related differences were seen for these analytes. Creatinine, uric acid, and bicarbonate showed an upward trend in values with increasing age, whereas aspartate aminotransferase, phosphorus, and total and ionized calcium showed a downward trend with increasing age. Sex-related differences were noted for these analytes. The immunoglobulins (IgG, IgA, and IgM) showed an upward trend with increasing age, with no sex-related differences except for IgM in children.     

Development of tyrosine aminotransferase and para-hydroxyphenylpyruvate dioxygenase activities in fetal and neonatal human liver.

In livers of fetuses of 220--340 g body wt, total cytosolic tyrosine aminotransferase activity was 1.0 nmol of product/mg of protein per min, and the corresponding values for autopsy livers of newborns of 740--1,475 g and 2,600--3,650 g were 1.5 and 5.7, respectively, as compared with the adult value of 12.7. On the other hand, para-hydroxyphenylpyruvate dioxygenase activity is at adult level already in fetuses less than 340 g body wt. The Km value for tyrosine of tyrosine aminotransferase (1 mM) was considerably higher than the corresponding value for para-hydroxyphenylpyruvate of para-hydroxyphenylpyruvate dioxygenase (50 micro M). These results suggest that tyrosine aminotransferase is the rate limiting enzyme in the catabolism of tyrosine in premature infants.     

Graphical analysis of laboratory data in the differential diagnosis of cholestasis: a computer-assisted prospective study

Data on 15 laboratory analytes obtained in 145 prospectively investigated cholestatic patients with viral hepatitis, chronic intrahepatic cholestasis and extrahepatic biliary obstruction were submitted to a computer-based graphical evaluation using probabilistic test analysis. This revealed a marginal utility for alkaline phosphatase, gamma-glutamyltransferase and the direct/total bilirubin ratio at specific cut-off points for the exclusion of extrahepatic cholestasis (PVneg 90%-100%). Aspartate aminotransferase and alanine aminotransferase values with cut-off points at 200 U/l and 300 U/l, respectively, were powerful discriminators between acute viral hepatitis and the other disease categories, while lactate dehydrogenase, erythrocyte sedimentation rate and the ratios gamma-glutamyltransferase/alanine aminotransferase as well as total bilirubin/gamma-glutamyltransferase were useful at specific cut-off points indicating the absence of this diagnosis (PVneg 92%-100%). An aspartate aminotransferase/alanine aminotransferase ratio above 1.5 and serum gamma-globulin concentrations above 20 g/l strongly suggested cholestasis due to chronic parenchymal liver disease (PVpos 92% and 90%, respectively). This graphical approach to laboratory data analysis enhances the understanding of the interrelations between cut-off points and sensitivity, specificity and predictive values and also of the influence of disease prevalence on disease prediction. It also adds to present knowledge by demonstrating the clinical relevance of several readily available, albeit rarely utilized diagnostic analytes.     

The pattern of serum biochemical abnormalities in patients with gallstones.

The sera from 144 patients (27 males and 117 females) with documented gallstones were assayed for eight different biochemical quantities, in order to study the pattern of specific biochemical changes in the blood of such patients and to establish any aetiologic relationship with gallstones. These quantities included: fasting glucose, alkaline phosphatase, alanine aminotransferase, total protein, albumin, total bilirubin, fasting total cholesterol, and fasting triacylglycerol. The same analysis was performed on sera obtained from 50 (9 males and 41 females) age- and sex-matched healthy controls. The statistical analysis showed that female patients had significantly higher values for fasting plasma glucose; alkaline phosphatase, total protein and albumin; and significantly lower values for bilirubin and total cholesterol than female controls. No overall differences in the levels of alanine aminotransferase and triacylglycerol were observed between the two female groups. Male patients on the other hand showed significantly higher values for fasting glucose and alkaline phosphatase than male controls. All other quantities, however, were not significantly different between the two male groups. When chemical analysis of the gallstones was performed, no consistent relationship was observed between the level of any of the above mentioned quantities and the chemical subtype of the gallstone (for both male and female patients). These data suggest that no specific serum biochemical pattern characterizes gallstone disease, and that there is no relationship between the stone type and the serum level of the studied quantities.     

Use of total patient data for indirect estimation of reference intervals for 40 clinical chemical analytes in Turkey.

In the present study we used patient data to calculate laboratory-specific indirect reference intervals. These values were compared with reference intervals obtained for a healthy group according to recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine and manufacturer suggestions. Laboratory results (422,919 records) from all subjects of 18-45 years of age over a 1-year period were retrieved from our laboratory information system and indirect reference intervals for 40 common analytes were estimated using a modified Bhattacharya procedure. Indirect reference intervals for most of the biochemical analytes were comparable, with small differences in lower [alkaline phosphatase (ALP) (male), alanine aminotransferase (ALT), creatine kinase, iron (male), total iron-binding capacity, folic acid, calcium (female), lactate dehydrogenase (LDH), lipoprotein (a) [Lp(a)], thyroid-stimulating hormone (TSH), total triiodothyronine (T(3)), direct bilirubin, apolipoprotein A-I (apoA-I), glucose, homocysteine, total cholesterol, ferritin, total protein, ceruloplasmin, sodium, blood urea nitrogen (BUN) and uric acid (female)] and/or upper limits [albumin, ALP (male), amylase, apoA-I, creatine kinase-MB (CK-MB), total iron-binding capacity, phosphorus, glucose, total cholesterol, gamma-glutamyltransferase (gamma-GT), magnesium, total protein, high-density lipoprotein cholesterol (HDL-C), total T(3), ALP (male), ALT, aspartate aminotransferase (AST) (male), direct bilirubin (male), creatine kinase, iron, folic acid (female), Lp(a), uric acid and triglycerides], to the reference intervals determined for healthy subjects in our laboratory. The indirect reference intervals, with the exception of a few parameters (creatinine, direct total bilirubin, calcium, BUN and potassium), were not similar to the reference intervals suggested by the manufacturers. We conclude that laboratory-specific reference intervals can be determined from stored data with a relatively easy and inexpensive method. Indirect reference intervals derived from stored data may be particularly suitable for the evaluation of results for the presenting population.     

Enzymatic assessment of myocardial injury after infarction or cardiac surgery. Is isoenzyme analysis required?

Estimation of enzyme release in plasma requires knowledge of the fractional catabolic rate constant (FCR) for the elimination enzyme activity from plasma. However, the total plasma content of such enzymes usually consists of several isoenzymes with different values of FCR. Thus, the use of a single overall value for FCR may cause error. This problem was studied by determination of the plasma isoenzyme activities of creatine kinase, lactate dehydrogenase, aspartate aminotransferase and alpha-hydroxybutyrate dehydrogenase in patients after cardiac surgery and after acute myocardial infarction. Values of FCR and the cumulative release of activity in plasma are estimated for separate isoenzymes and for total enzyme activity. Results are compared with the enzyme content of myocardium, skeletal muscle and blood cells. It is concluded that isoenzyme separation is not required for the quantitative use of such data. The implications for the validation of enzymatic estimation of cardiac injury are discussed. The results indicate that local inactivation of enzymes after cardiac injury must be limited.     

Establishing pediatric reference intervals for 13 biochemical analytes derived from normal subjects in a pediatric endocrinology clinic in Korea

ObjectivesDefining pediatric reference intervals is one of the most difficult tasks for laboratory physicians. The continuously changing physiology of growing children makes their laboratory values moving targets. In addition, ethnic and behavioral differences might also cause variations. The aim of this study was to establish age- and sex-specific partitioned reference intervals for 13 serum biochemical analytes in Korean children.Design and methodsA total of 2474 patients, girls aged 2–14 years and boys aged 2–16 years, who underwent a short stature workup but were diagnosed as normal at the Pediatric Endocrinology Clinic of Severance Hospital (Seoul, Korea) between September 2010 and June 2012 were included in this study. The levels of serum calcium, inorganic phosphorus, blood urea nitrogen, creatinine, uric acid, glucose, total cholesterol, total protein, albumin, alkaline phosphatase, aspartic aminotransferase, alanine aminotransferase, and total bilirubin were measured using a Hitachi 7600 analyzer (Hitachi High-Technologies Corporation, Tokyo, Japan). Reference intervals were partitioned according to sex or age subgroups using the Harris and Boyd method.ResultsMost analytes except calcium and albumin required partitioning either by sex or age. Age-specific partitioned reference intervals for alkaline phosphatase, creatinine, and total bilirubin were established for both males and females after being partitioned by sex. Additional age-specific partitioning of aspartic aminotransferase in females and total protein and uric acid in males was also required. Inorganic phosphorus, total cholesterol, alanine aminotransferase, blood urea nitrogen, and glucose were partitioned only by sex.ConclusionsThis study provided updated age- and sex-specific pediatric reference intervals for 13 basic serum chemistry analytes from a sufficient number of healthy children by using a modern analytical chemistry platform.     

Reference values for free amino acids and other biochemical constituents in serum of male rabbits

Reference values for free amino acids in male rabbits (n = 145) were determined by gas chromatography. In addition, reference values for glucose, serum transaminase activities (aspartate aminotransferase, alanine aminotransferase), and serum protein fractions are reported.     

内镜逆行胰胆管造影术中局部抗生素灌洗降低胆道结石复发率的研究

目的探讨内镜逆行胰胆管造影术(ERCP)术中局部抗生素灌洗降低胆道结石复发率的效果。方法胆道结石患者180例根据随机抽签法分为治疗组与对照组各90例,两组都给予ERCP手术治疗,同时治疗组在术中给予局部抗生素灌洗治疗,观察两组的近期效果,同时随访调查胆道结石复发情况。结果治疗组的一次与二次取净结石比例分别为91.1%和100.0%,对照组分别为90.0%和100.0%,组间对比差异无统计学意义(P0.05)。术后14天治疗组与对照组的治疗有效率分别为96.7%和87.8%,治疗组的治疗有效率明显高于对照组(P0.05)。治疗组术后14天内急性胰腺炎、胆管炎、消化道出血和消化道穿孔等并发症发生情况明显少于对照组(P0.05)。手术之后两组直接胆红素(DB)和总胆红素(TBIL)、血清谷丙转氨酶(ALT)和谷草转氨酶(AST)的含量都大幅度减少(P0.05),并且对照组上述4种物质的含量要高于治疗组(P0.05)。所有患者术后随访调查6个月,治疗组的复发率为2.2%(2/90),对照组为11.1%(10/90),治疗组术后复发率明显低于对照组(P0.05)。结论 ERCP术治疗胆道结石具有很高的成功率,局部抗生素灌洗的应用能促进恢复肝胆的生理学功能,减少并发症的发生,提高总体治疗疗效,也有利于降低胆道结石的复发,有很好的应用价值。     

The estimation of ammonia in kidney slices in the presence of added glutamine and other amino acids.

This paper reports a study of changes in red blood cell enzymes and some serum parameters during and after treatment of protein-calorie malnutrition. The red cell GSH levels were low during the crisis, together with the levels of GSSG:NADPH reductase, GSH:H₂O₂ peroxidase, aspartate aminotransferase and alanine aminotransferase. After treatment the levels of all these enzymes increased significantly to normal values.Of the serum parameters investigated, significant reduction in the activity of the enzymes cholinesterase, catecholamine oxidase, total proteins, albumin, urea and electrolytes were obvious, and returned to normal values after treatment. Ceruloplasmin activity remained low even after three weeks' treatment and could not be related to copper levels.The results are discussed in relation to anemia and liver damage that may accompany the syndrome.     

Haemolysis as an interference factor in clinical chemistry

Using fully mechanized analytical equipment, interference by haemolysis in the determination of 26 clinical chemical parameters was determined quantitatively by adding haemolysate to serum. Haemoglobin concentrations up to 6.6 g/l caused essentially no interference in the following determinations: albumin (immuno-nephelometric), alpha-amylase, calcium, chloride, cholesterol, cholinesterase, creatinine, iron, glucose, glutamate dehydrogenase, uric acid, urea, sodium, inorganic phosphate, total protein, transferrin and triglycerides. In the presence of haemoglobin, erroneously high values were found for: lactate dehydrogenase (haemoglobin higher than 0.2 g/l), aspartate aminotransferase, potassium and acid phosphate (haemoglobin higher than 1.5 g/l), creatine kinase (haemoglobin higher than 2.5 g/l) and alanine aminotransferase (haemoglobin higher than 3.4 g/l). Erroneously low values were found for bilirubin (haemoglobin higher than 0.8 g/l), alkaline phosphatase and albumin (by electrophoresis) (haemoglobin higher than 1.5 g/l) and gamma-glutamyltransferase (haemoglobin higher than 3.0 g/l).     

Variability of glutathione S-transferase alpha in human liver and plasma

BACKGROUND: Glutathione S-transferases are a family of enzymes involved in the binding, transport, and detoxification of a wide variety of endogenous and exogenous compounds. Little information is available about the variability of class alpha glutathione S-transferases in human liver, where they are highly expressed, or in serum. METHODS: Both total class alpha glutathione S-transferase (GST-alpha, composed of GSTA1-1, GSTA1-2, and GSTA2-2) as well as GSTA1-1 concentrations were measured by specific and sensitive ELISA in liver cytosols of 35 organ donors and in plasma samples of 350 healthy controls. RESULTS: The mean total GST-alpha and GSTA1-1 in liver cytosols were 25.1 +/- 9.4 and 10.7 +/- 5.3 microg/mg protein, respectively, and did not correlate with activities of aspartate aminotransferase or alanine aminotransferase. The mean total GST-alpha in liver was significantly higher in females compared with males (28.8 +/- 10.0 vs 22.0 +/- 7.8 microg/mg protein; P <0.05). In contrast, the median total GST-alpha in plasma was lower in females compared with males (2.0 and 2.8 microg/L, respectively; P <0.0001). The median ratios for GSTA1-1/total GST-alpha in liver and plasma were 0.42 and 0.58, respectively. CONCLUSIONS: GSTA1-1 constitutes approximately one-half of the total amount of alpha class GSTs in human plasma and liver. Total GST-alpha values are higher in female liver but lower in plasma compared with the respective values in males.     

Indirect reference limits estimated from patients' results by three mathematical procedures

Presently, only a few clinical laboratories produce their own reference values, while the great majority use reference intervals reported in the literature. An alternative to this unsatisfactory situation is to estimate indirect reference limits by means of mathematical/statistical procedures from patients' results obtained routinely in the laboratory. The procedures of Bhattacharya (A simple method of resolution of a distribution into Gaussian components. Biometrics 1967;23:115-135) Martin et al. (Reference values based on populations accessible to hospitals. In: Gr?sbeck R, Alstr?m T, editors. Reference Values in Laboratory Medicine. Chischester: Wiley, 1981:233-262) and Kairisto et al. (Generation of reference values for cardiac enzymes from hospital admission laboratory data. Eur J Clin Chem Clin Biochem 1994;32:789-796) were applied to 14 biochemical quantities. In order to verify these procedures, the indirect reference limits obtained from patients' results were validated by statistical comparison with reference limits estimated from a reference sample according to recommendations of the International Federation of Clinical Chemistry (IFCC). Calculated indirect reference limits for most quantities studied were reliable, but indirect reference limits for bilirubins and potassium ion substance concentrations, alanine aminotransferase, and aspartate aminotransferase catalytic concentrations in serum were not suitable. We conclude that indirect reference limits can be obtained from patients' results by all procedures studied when skewness and kurtosis of mixed distribution are not too large, but other factors also seem to have an influence on the reliability of these procedures.     

Predictive values of various liver function tests with respect to the diagnosis of liver disease

A prospective study of 181 patients suspected of having liver disease was carried out to determine the relative efficiencies of serum bilirubin (total and direct), alkaline phosphatase (AP), gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) with respect to diagnosis. Liver biopsies, liver scans, abdominal ultrasound, and clinical parameters were also tabulated and used independently to evaluate the patient's hepatic status and to determine the final diagnoses in each case. From the results of these tests for the 60 patients who were diagnosed as having liver disease, and the 87 patients who were felt to be free of liver disease, predictive values of the above tests were established. Data from this study suggests that while direct bilirubin is the most specific test, GGT is the most sensitive and has the fewest false negatives in the diagnosis of liver disease.     

Post-transfusion hepatitis after open-heart surgery in Finland—a prospective study

Summary. A countrywide prospective study on open-heart surgery patients was performed between 1987 and 1989 to determine the prevalence and nature of post-transfusion hepatitis in Finland. Altogether 685 coronary by-pass operation patients, who received on average 12·3 units of blood products, were postoperatively followed for 6 months. Ten blood samples were drawn from each patient. Hepatitis was diagnosed when the alanine aminotransferase values exceeded the upper normal value 2·5 times in one sample and twice in another, and non-viral causes could reasonably be excluded. Eleven hepatitis cases (1·6%) were recorded with a mean incubation period of 8·4 weeks; all represented the non-A, non-B type. The majority had mild symptoms or were asymptomatic but two became icteric. Six patients (55%) had abnormal alanine aminotransferase values for at least 6 months, which indicates possible chronicity. These 685 open-heart surgery patients received a total of 8,436 units of blood products; thus the rate of NANBH cases per 1000 units was as low as 1·3. This is less than recently reported in six other prospective studies.     

The effects of ethanol (0.75 g/kg body weight) on the activities of selected enzymes in sera of healthy young adults: 1. Intermediate-term effects.

We report the intermediate-term effects of three consecutive evenings of moderate ethanol ingestion (0.75 g/kg body weight each evening) on activity values for alkaline phosphatase, gamma-glutamyltransferase, creatine kinase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in sera of nine apparently healthy young adults. We define "intermediate-term" effects as those occurring between 10 h and 100 h after completion of the ethanol consumption schedule. The most pronounced changes in enzyme activity for the group of volunteers were: gamma-glutamyltransferase, +25% at 60 h after ethanol ingestion; alanine aminotransferase, +12% at 60 h after ethanol; and aspartate aminotransferase,--12% at 60 h after ethanol. All three enzymes exhibited similar time courses, i.e., mean peak activity changes were observed at 60 h, and all three mean enzyme activity values returned to near baseline by 100 h. The possible explanations for the observed changes and the clinical significance are discussed.     

Computer-controlled instrument system for sequential chemical testing III. Application to liver assessment.

We used the previously described [Clin. Chem. 19, 1114 (1973)] and evaluated [Clin. Chem. 19, 1122 (1973)] computer-controlled instrument system for sequential chemical testing to select and perform tests of hepatic status, to aid the clinician in the diagnosis of liver disease. Results for total bilirubin, aspartate aminotransferase, and alkaline phosphatase obtained from the continuous-flow analysis (SMA 12/60) admission screen were used by the instrument system to determine selectively the values for gamma-glutamyltransferase, alanine aminotransferase, creatine kinase, and total and direct bilirubin. Kit methods for the latter four tests were evaluated on the system; results were similar to manual procedures. A software, enzymatic ratemeter was found to be better than the previously described hardware ratemeter. The follow-up tests of serum prescribed by the system are compared to clinician-prescribed follow-up tests and discharge diagnoses. In 10 of 19 cases, the system and clinician ordered similar follow-up tests; in three cases follow-up differed, and in six cases, the system ordered follow-up tests and the clinician ordered none.