bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the Diagnostic Utility of Timed Serial (Slope) Creatine Kinase Measurements with Conventional Serum Tests in the Early Diagnosis of Myocardial Infarction
Authors: Leung Fred Y , Griffith Annette P , Jablonsky George , Henderson A Ralph
Published: February 2014

We compared the diagnostic utility of recently proposed slope assays for serum creatine kinase and creatine kinase-2 with the optimized decision threshold assays. The former approach has been claimed to be superior to any other single diagnostic technique. We show, by ROC curve and likelihood ratio analyses, that the total creatine kinase slope assay possesses the same diagnostic power, when confidence intervals are used, as the optimized decision threshold assay. Moreover, slope assays of creatine kinase-2 were diagnostically inferior to the optimized decision threshold assays. Indeed, these latter, optimized, assays have the highest likelihood ratios for a positive test result of the available assays, and they should always be used in situations of diagnostic doubt.
Specificity of Two-Site Immunometric Assays
Authors: Perry B , Chapman R S , McConway M G , Griffin D , Beastall G H
Published: February 2014

The assessment of specificity in two-site immunometric assays is complex. Conventional approaches based on standard substitution with cross-reactant may yield misleading results. An ‘in-house’ immunoradiometric assay (IRMA) for human growth hormone (hGH) appeared free from cross-reactivity with human placental lactogen (hPL) in a single point standard substitution experiment performed by the United Kingdom External Quality Assessment Scheme (UK EQAS). However, detailed studies based on the substitution of hGH standards with hPL cross-reactant, the addition of hPL cross-reactant to hGH standards and the recovery of added hGH from endogenous cross-reactant (sera from pregnant subjects) revealed gross cross-reactivity of hPL in the hGH assay. We recommend that the validation of assay specificity should require the demonstration of quantitative recovery of a range of analyte concentrations from human sera that contain varying endogenous concentrations of cross-reactant.
Scintillation Proximity Assay: Determination of Steroid Hormones without Separation of Antibody-Bound and Free Ligand
Authors: Swinkels L M J W , Ross H A , Benraad Th J
Published: February 2014

Scintillation proximity assay (SPA), which does not require the physical separation of bound and free hormone, was applied to the determination of Cortisol in plasma. Results showed excellent agreement with a conventional radioimmunoassay using dextran-coated charcoal to separate bound and free Cortisol, with similar precision and sensitivity.

When the SPA was applied to the measurement of plasma aldosterone, it was evident from the SPA and radioimmunoassay results that the blocking of aldosterone binding to corticosteroid-binding globulin by 8-amino-1-naphthalene-sulphonic acid was not completely effective, and that a different sample preparation technique should be used.

SPA may become the method of choice for the determination of hormones in blood.
Progress in Immunoassays for Serum Prolactin: Evidence from the UK External Quality Assessment Scheme (EQAS) 1980–1989
Authors: Harming I , Seth J , Bacon R R A , Hunter W M , Al-Sadie R
Published: February 2014

The quality of serum prolactin assays routinely performed by UK laboratories has been monitored in an external quality assessment scheme (EQAS) over a 10-year period, during which participation in the EQAS increased three-fold, and considerable changes in methods and standardization were introduced. The all-laboratory mean was used as the sample target value, and proved to be stable and accurate. Overall between-laboratory agreement in the clinically important range improved from a geometric coefficient of variation (GCV) of 25% to 14%. This appears to reflect the increased use of kits in place of ‘in-house’ assays, the more widespread availability of international standards and the absence of any marked differences in bias between the commonly used methods. Published guidelines on the clinical interpretation of prolactin values should, therefore, be widely applicable. The EQAS data indicate that, in general, the quality of performance of prolactin assays is adequate for their clinical application.
The Analysis of Bilirubin in Serum
Authors: Westwood A
Published: February 2014

The most widely used methods for the assay of total bilirubin in serum are based on a coupling reaction with various diazo dyes in the presence of an accelerating agent. The ‘direct’ reaction, without accelerator, gives a good estimate of the conjugated and protein bound (δ) species of bilirubin only if carefully standardized reaction conditions are used. Enzymatic methods based on bilirubin oxidase appear to give similar results, for both total and direct bilirubin, and through difficult to calibrate, spectrophotometric methods can also give reliable results for total bilirubin at the higher concentrations seen in neonates. More sophisticated HPLC or dry-slide techniques are required for the specific assay of the various conjugated and protein-bound species of bilirubin in serum.
Calcium and Phosphorus Metabolism in the Premature Infant
Authors: Mayne P D , Kovar I Z
Published: February 2014

During the last trimester of pregnancy, there is a sixfold increase in fetal calcium and phosphorus accumulation. Unsupplemented human breast milk may not provide sufficient calcium and phosphorus for the rapdily growing preterm infant to match the accumulation that should have taken place in utero and to permit normal bone mineralization.

Rickets of prematurity may present clinically between the 6th and 12th postnatal week. The clinical diagnosis may be confirmed using simple biochemical tests. Inadequate mineral substrate intake, particularly of phosphorus, is the most common cause, although a delay in the maturation of the renal enzyme, 1-α hydroxylase, with low plasma concentrations of 1,25-dihydroxyvitamin D, may also occur. The biochemical response to treatment can be determined by documenting a fall in plasma alkaline phosphatase activity and a rise in plasma phosphate concentration and urinary phosphate excretion.
Development and Evaluation of the Simultaneous Determination of Sweat Sodium and Chloride by Ion-Selective Electrodes
Authors: Barbour Heather M
Published: February 2014

A method for the simultaneous determination of sweat sodium and chloride was developed and evaluated using a Monarch 2000 centrifugal analyser with ion-selective electrodes. In order to measure sodium and chloride in diluted sweat samples and sweat paper eluates an analytical working range of below 10 mmol/L was required. This was achieved by modification of the Monarch ISE software parameters for urine electrolytes together with the use of calibrators within this range. Evaluation of the method has included linearity, recovery and precision studies and the correlation between ion-selective electrode and flame photometry for sweat sodium and between ion-selective electrode and a continuous flow method for sweat chloride. Of the patients studied so far, there has been good discrimination in sweat electrolytes between those with and without cystic fibrosis.
Preanalytical Errors in Ionized Calcium Measurements Induced by the Use of Liquid Heparin
Authors: Sachs Ch , Rabouine Ph , Chaneac M , Kindermans C , Dechaux M , Falch-Christiansen T
Published: February 2014

The use of heparin in a liquid form to measure ionized calcium (Ca+ +) in plasma or whole blood can induce preanalytical errors by dilution and by changing the original Ca+ + value by binding or by re-equilibration with calcium in the anticoagulant solution.

To quantify these errors, Ca+ + was measured on serum pools under different sampling conditions. Incomplete syringe filling and specimen volume/syringe nominal volume ratio effects were tested. Syringes were rinsed with saline to yield pure dilution effects, with sodium heparinate to study binding and with calcium-titrated heparinate to evaluate ‘calcium-distortion’. Detailed tables provide percentage error values for all sampling conditions. Dilution errors could reach − 5% and binding was always important (− 14 to − 50%). Distortion was minimal around 1·25 mmol/L but could reach − 4% for high and + 8% for low Ca+ + values. Errors increased when syringes were not filled to their nominal volume, especially with small-sized specimens.
Improved Procedure for the Second-Derivative Spectrophotometric Analysis of Carboxyhaemoglobin
Authors: Verweij H , Bonte H A
Published: February 2014

We describe a modification of the second-derivative spectrophotometric assay for carboxyhaemoglobin in blood. Using the original procedure we have often observed a time-dependent change in the signal leading to unreliable results. By using phosphate-buffered-saline (pH 7·4) instead of ammonia to dissolve the deoxygenating agent (sodium dithionite), we obtained stable and reproducible second-derivative signals from which the percentage carboxyhaemoglobin in the patients' samples can be calculated.
Differential Response of Serum Alkaline Phosphatase and Serum Osteocalcin in Paget'S Osteosarcoma
Authors: Davie M W J , Worsfold M , Sharp C A
Published: February 2014

Serum osteocalcin did not show any response to the onset of osteosarcoma in Paget's disease of bone whereas serum alkaline phosphatase increased rapidly. This suggests that osteocalcin is not useful in the diagnosis and management of Paget's osteosarcoma and does not reflect the same osteoblastic processes in bone as serum alkaline phosphatase.
Alcohol and the Laboratory in the United Kingdom
Authors: Wright J W
Published: February 2014

Reliable and rapid assays for the measurement of ethanol in breath and body fluids are now widely available. In view of the importance of alcohol abuse as a cause of a wide variety of both acute and chronic clinical conditions, hospital laboratories should be prepared to perform these assays for clinical purposes, although many will choose not to become involved in the assay of medico-legal samples.
Pseudohyperphosphataemia in Multiple Myeloma
Authors: Hawkins Robert C W
Published: February 2014

Two cases of spurious hyperphosphataemia in patients with multiple myeloma are presented. An unreduced phosphomolybdate method without dialysis was used and the falsely raised values are shown to be due to the formation of a proteinaceous suspension in the reaction mixture. Such interference may be more prevalent than is generally recognized, and care should be taken to identify the problem in patients with myeloma.
Effects of Ionic Strength on Ionized Calcium Measured Using Reference Electrode Liquid Junctions of Varying Design and Composition
Authors: Payne R B
Published: February 2014

Five commercial analysers were used to measure ionized calcium in aqueous and protein solutions which contained the same amount of calcium but had sodium chloride concentrations ranging from 100 to 150 mmol/L. In aqueous solutions measured activity fell significantly with increasing ionic strength while in protein solutions it increased. When isotonic sodium chloride was substituted for the hypertonic potassium chloride reference electrode liquid junction of an analyser with an open junction, there was a marked positive change in the effect of ionic strength in both aqueous and protein solutions. In contrast, when either isotonic sodium chloride or potassium chloride was substituted for the hypertonic potassium chloride of an instrument with a membrane-restricted junction, there was no effect on the change of measured values with ionic strength. Increasing the protein concentration by ultrafiltration did not change ionized calcium values when isotonic reference solutions were used with either open or membrane-restricted junctions.

Because membrane-restricted isotonic junctions respond like hypertonic junctions to changes in sample ionic strength but do not exhibit protein interference, they may prove to have advantages over both open isotonic junctions and all configurations of hypertonic junction for measurements in patients.
Overestimation of Monoclonal Immunoglobulin by Immunochemical Methods
Authors: Riches Pamela G , Sheldon Joanna , Smith A M , Hobbs J R
Published: February 2014

A comparison of paraprotein estimation by scanning densitometry with corresponding immunoglobulin concentration measured by rate immunonephelometry, fixed-time immunonephelometry and kinetic immunoturbidimetry using a large number of sera has indicated overestimation of the immunoglobulin by liquid phase immunoassays in the presence of a monoclonal component. The effect was seen with all three major immunoglobulin isotypes but was most marked with IgM paraproteins when measured by kinetic nephelometry. The overestimations could not be explained by presence of rheumatoid factors or immune complexes in the serum samples, or by non-parallelism, over a range of dilutions, of the reaction of sample and calibrant with the antiserum. The source and species of antiserum used was a major contributory factor.
Fructosamine in Diabetes Screening of the Elderly
Authors: Croxson S C M , Absalom S , Burden A C
Published: February 2014

The use of serum fructosamine in diabetes detection was investigated during a diabetes survey performed with a modified oral glucose tolerance test (MOGTT) on 742 residents of the Melton Mowbray area aged between 65 and 85 years. Subjects were tested in the morning and remained at rest. MOGTT results were classified by WHO criteria. The fructosamine concentration was measured in a random sub-group of 264 normal subjects and had a Gaussian distribution (mean = 1 · 67 mmol/L, SD = 0 · 126 mmol/L). In the survey as a whole 25 new diabetics were found of which 23 had fructosamine measured; 17 had values above the 95th percentile and four more had values above the 90th percentile. We have found fructosamine concentration to be a useful screen for diabetes but this may be dependent upon the standardized sampling procedure used, and the population studied.
Enzymatic Determination of Bilirubin in Serum of Newborns—Any Advantage over Previous Methods?
Authors: Schlebusch H , Schneider Ch
Published: February 2014

Using a Hitachi 705 Selective Analyzer at 25 °C, precision and accuracy of the enzymatic determination of total bilirubin (DRI-STAT®) in serum of newborns was studied. Imprecision (day-to-day) was unacceptably high using daily calibration, but could be reduced by using a fixed factor. Accuracy was checked by analysis of 70 newborn sera with the ‘Candidate Reference Method’ and DRI-STAT®. It could be improved using calibrators with reference method values. Haemoglobin interference was studied by addition of different derivatives of fetal haemoglobin (oxihaemoglobin, desoxihaemoglobin, haemiglobin) to pools of newborn sera and control samples. DRI-STAT® is more susceptible to interference by oxihaemoglobin than other routine methods. No difference was found in the influence of oxhihaemoglobin and desoxihaemoglobin; haemiglobin interferes significantly less.
Post-Traumatic Hypothalamic-Pituitary Dysfunction Presenting with Biochemical Features of Primary Hypothyroidism
Authors: Gunn I R , Beastall G H , Matthews D M , Bath J C J L
Published: February 2014

Two cases of post-traumatic hypothalamic-pituitary dysfunction are described where the primary pathology was shown to be understimulation of the pituitary by hypothalamic hormones. In each case, the biochemical presentation was a low serum thyroxine and elevated TSH concentration mimicking primary hypothyroidism. Treatment with thyroxine before Cortisol replacement was not beneficial. In both cases, hydrocortisone therapy alone resulted in a rise in serum thyroxine and fall in serum TSH. Chronic Cortisol deficiency may directly impair the thyroid response to TSH, whilst thyroxine appears to exert its feedback primarily at pituitary rather than hypothalamic level.
Safe, Stable, Whole Blood Samples for Quality Assessment of Glucose Measurement by Non-Laboratory Staff
Authors: Ambler Jeffrey , Brown Nigel S , Walker Geoffrey
Published: February 2014

A whole blood control material has been used to assess the analytical performance of non-laboratory staff who use glucose meters in clinical areas. It is prepared from sterile horse blood which is readily available from a commercial source. There are no known infection or disease transmission risks to users. When the material is stabilized by the addition of sodium fluoride less than 3% loss of glucose over 48 h is observed from an initial value of 10 mmol/L. However, we prefer to stipulate that the glucose is measured on the day of receipt. The material has been used successfully with Reflolux IIM meters and B-M sticks (Boehringer Mannheim, UK) for over a year in our hospital.
Screening for Hyperlipidaemia in Diabetes Mellitus. Relationship to Glycaemic Control
Authors: Paterson J R , Pettigrew A R , Dominiczak M H , Small M
Published: February 2014

Diabetic patients have an increased risk of developing cardiovascular disease which, in part, may be due to lipid abnormalities. Our aim was to establish from an initial screening programme what proportion of diabetic patients attending a routine diabetic outpatient clinic had hyperlipidaemia despite having good or acceptable glycaemic control. We screened 299 randomly selected diabetic patients to assess the prevalence of hyperlipidaemia and its relationship to glycaemic control. Twenty-eight per cent had hyperlipidaemia (defined as cholesterol > 6 · 5 mmol/L and/or non-fasting triglycerides > 3 mmol/L). Of these hyperlipidaemic patients, 71% had good or acceptable glycaemic control as defined by a glycated haemoglobin value of < 10%. Approximately 40% of type 2 diabetic patients had body mass index values outside recommended targets indicating the potential of weight reduction in this group as a treatment modality. Our results indicate that the majority of hyperlipidaemic diabetic patients had good or acceptable glycaemic control, and as such these patients are potential candidates for specific lipid lowering therapy.
Chemical Diagnosis of Fabry's Disease by Fluorometric Assay and Fast Atom Bombardment/Mass Spectrometry
Authors: Nakanishi Toyofumi , Funahashi Shuji , Funai Tatsuhiko , Hashimoto Takenori , Shimizu Akira
Published: February 2014

We report the results of a fluorometric assay for α-galactosidase A (EC.3.2.1.22) in plasma and leukocytes, and fast atom bombardment/mass spectrometry (FAB/MS) analysis of glycosphingolipids in urine sediments from a patient with Fabry's disease. In plasma, this patient had only 5 · 0% of the normal amount of α-galactosidase A, and his brother and mother had 11 · 0% and 25 · 0%, respectively. In leukocytes, the activities were below 8 · 0%. Glycosphingolipids from urine sediments were partially purified using a Sep-Pack C18 cartridge.

The chemical diagnosis of Fabry's disease can be made more rapidly and accurately using fluorometric and FAB/MS analyses.
Potential of Descriptive Linear Discriminant Analysis for Studying Clinical Chemical and Haematological Data from Persons with Heterozygous Sickle Cell Disease
Authors: Volmer Marcel , Muskiet Frits A J , Hindriks Frans R , van der Slik Willem
Published: February 2014

To study the potential of multivariate classification methods in order to obtain more insight into abnormal laboratory data from patients with sickle cell disease, we investigated standard haematological and clinical chemical variables of 18 controls and 37 apparently healthy persons with heterozygous sickle cell disease (Hb AS), all women, using both univariate and multivariate classification methods. In the univariate method, those with Hb AS showed decreased serum log aspartate aminotransferase (log AST) activity, mean corpuscular volume and mean corpuscular haemoglobin (MCH) and increased sodium concentration. The multivariate method identified sodium, potassium, urea, uric acid, log AST, alanine aminotransferase and MCH as the variables that produced maximal separation between persons with Hb AS and controls. It increased the ‘non-error rate’ for classification of persons with Hb AS by 16 · 4% compared with classification based on the variable, MCH, that produced maximal separation by the univariate method.

The frequency distribution of percentage Hb S in the Hb AS group proved bimodal with maximal separation at 37 · 0% Hb S. The subgroup with 37 · 0% or less ( n = 16) was considered to have concomitant heterozygous α-thalassaemia-2. In the univariate method the subgroup characterized by > 37 · 0% Hb S ( n = 21) had increased serum sodium and uric acid concentrations, perhaps related to sickle cell nephropathy, whereas the subgroup with ≤ 37% Hb S did not. The multivariate method added information to the univariate method by additionally identifying abnormalities in serum potassium and urea concentrations in the former subgroup. The differences in variables related to renal function may result from a decreasing tendency of erythrocytes to sickle with decreasing percentage of Hb S, and show that even apparently healthy persons with Hb AS are heterogeneous with respect to the development of abnormalities demonstrable by clinical chemistry.
Use of a Non-Extraction HPLC Technique for Measuring Angiotensin-Converting Enzyme under Optimum Conditions
Authors: Badminton M N , Dawson C M , Rainbow S J , Tickner T R
Published: February 2014

A non-extraction high performance liquid chromatography assisted method for the measurement of angiotensin-converting enzyme in serum has been developed. Serum containing the enzyme was incubated with the synthetic substrate, furylacryloylphenylalanylglycylglycine at a concentration approaching 10 times the apparent Km, prior to injection onto a shielded hydrophobic reverse phase high performance liquid chromatography column. This allowed the product to be separated and measured directly without the need for a time consuming protein extraction step. The method is enzymatically sound and avoids the methodological problems associated with automated kinetic assays.
Development of a Rapid Latex Enhanced Turbidimetric Assay for Retinol Binding Protein in Urine
Authors: Thakkar H , Cornelius J , Dronfield D M , Medcalf E A , Newman D J , Price C P
Published: February 2014

We describe a simple, rapid and sensitive homogeneous immunoassay for urinary retinol-binding protein (RBP) using latex particle-enhanced turbidimetric immunoassay. Rabbit anti-human RBP is covalently coupled to 40 nm latex particles and the assay performed on the IL Monarch 2000 centrifugal analyser, with a 20 μL sample volume and the reaction monitored at 340 nm over an 8 min period. The assay range is 0–6 mg/L with a detection limit of 25 μg/L. The within and between assay coefficients of variation are less than 1 · 5% and less than 2 · 5%, respectively. Comparison with radioimmunoassay for RBP showed good agreement.
Clinical Value of Apolipoprotein Measurement
Authors: Bhatnagar D , Durrington P N
Published: February 2014

Low density and very low density lipoproteins contain apolipoprotein B100 which is synthesized in the liver. Chylomicrons have apolipoprotein B48, which consists of part of the apolipoprotein B100 sequence, and which is produced in the gut by the same gene that encodes for apolipoprotein B100. Both apolipoprotein B100 and apolipoprotein B48 are important for the secretion of triglyceride-rich lipoproteins whereas apolipoprotein B100, which can bind to the low density lipoprotein receptor, is also important for low density lipoprotein catabolism. Apolipoprotein (a) has structural homology with plasminogen and exists as a complex with apolipoprotein B100 in lipoprotein (a). Apolipoprotein AI is the main lipoprotein in high density lipoproteins, whilst apolipoprotein E, present in chylomicrons and intermediate density lipoproteins, plays a major role in their catabolism.

Serum apolipoprotein B and apolipoprotein AI have potential in the evaluation of coronary risk. Apolipoprotein B may be of particular value in patients with hypertriglyceridaemia and normal low density lipoprotein cholesterol levels. Apolipoprotein (a) has also been reported to be an important indicator of coronary risk, especially in the presence of elevated apolipoprotein B. Lack of standardization and the limited availability of prospective data at present limit the routine use of apolipoprotein B, AI and (a) measurements. The determination of apolipoprotein E phenotypes has proved useful in the diagnosis of remnant (type III) hyperlipoproteinaemia.
Medical Training in Clinical Biochemistry (Chemical Pathology) in Scotland 1985–1989
Authors: Paterson J R , Simpson W G , Neithercut W D
Published: February 2014

A questionnaire was sent to 35 doctors who were believed to have trained in clinical biochemistry in Scotland between 1 January 1985 and 31 December 1989. Thirty replies were received from 23 individuals who were still employed in the speciality (including seven consultants and nine senior registrars) and from seven individuals who had left. Twenty considered that training within the laboratories in which they were employed had not been satisfactory. The main emphasis of training was directed towards reporting duties, clinical liaison, research, teaching and outpatient clinics. Little training was provided for the development of analytical experience, personnel selection and laboratory management. Those surveyed identified poor training in laboratory management as the main aspect of training which required improvement.
Effect of Fasting, Self-Selected and Isocaloric Glucose and Fat Meals and Intravenous Feeding on Plasma Zinc Concentrations
Authors: Goode Helen F , Robertson D A F , Kelleher J , Walker B E
Published: February 2014

This study investigated the effect of fasting, self-selected meals and isocaloric oral glucose and fat meals and intravenous (i.v.) feeding on plasma zinc concentrations in men.

Plasma zinc remained stable when volunteers fasted all day, but self-selected meals and 600 kCal of dextrose or fat emulsion caused significantly reduced plasma zinc concentrations [mean(SD) 12 · 1 (1 · 4), 12 · 3 (0 · 6) and 12 · 2 (0 · 7) μmol/L at 1400 h, respectively, compared with a fasting level of 13 · 9 (1 · 6) μmol/L at 0800 h, P < 0 · 05]. In patients undergoing intravenous hyperalimentation, plasma zinc decreased from 12 · 0(1 · 4) μmol/L at 0800 h to 10 · 0 (1 · 1) μmol/L at 1400 h [mean(SD), P < 0 · 01].

These data show that both enteral and i.v. feeding cause a decline in plasma zinc and that glucose alone is not responsible for this post-prandial fall since ingestion of isocaloric amounts of glucose or fat have a similar effect.
The Effect of a Standard Oral Calcium Load Given in Two Different Forms on Plasma Ionized Calcium and Serum PTH
Authors: Bailey Ian R
Published: February 2014

A standard dose (1 g, 25 · 4 mmol) of calcium was administered both as calcium chloride in syrup and as Calcium-Sandoz Syrup (calcium glubionate and calcium galactogluconate) to 10 volunteers. Both dosage forms caused a significant rise in ionized calcium and a significant fall in concentration of serum PTH, the calcium chloride producing significantly greater changes. The urinary excretion of calcium measured over 5 h after calcium chloride was double that after Calcium-Sandoz. Calcium chloride, as expected, also gave rise to a decreased urine pH. Calcium chloride would be the better choice for an oral PTH suppression test.
A Simple Approach to Screening for Microalbuminuria in a Type 1 (Insulin-Dependent) Diabetic Population
Authors: McHardy K C , Gann M E , Ross I S , Pearson D W M
Published: February 2014

The reproducibility of albumin concentration in first-morning samples of urine was assessed in 334 insulin-dependent diabetic patients aged 18–60 years. The albumin excretion rate was determined immunoturbidimetrically in three sterile, Albustix-negative, first-morning urine samples submitted over a week. An abnormally high mean value, ≥2 · 5 mg albumin per mmol creatinine (Ua/Uc), was found in 33 patients (9 · 9%). These patients were older (mean 42 vs 34 years, P < 0 · 01), had longer disease duration (18 vs 14 years, P < 0 · 01) and higher HbA1c values (6 · 8 vs 6 · 3%, P < 0 · 05) than those without microalbuminuria. Although triplicate samples were collected within 7 days, Ua/Uc showed considerable intraindividual variation, with a mean coefficient of variation of 49%. Despite this it was found that Ua/Uc values greater than 1 mg/mmol on the first specimen had a sensitivity of 97% and a specificity of 82% for detecting those with a three-sample mean value greater than 2 · 5 mg/mmol. Thus virtually all those with microalbuminuria (32/33) had a single first-morning result greater than 1 mg/mmol, and in those with a lower ratio microalbuminuria was excluded with more than 99% certainty.
External Quality Assessment of Total Urinary Protein Estimation in the United Kingdom
Authors: Chambers Robin E , Bullock David G , Whicher John T
Published: February 2014

Three surveys of total urinary protein quantitation have been carried out in 350 UK laboratories. The seven specimens comprised buffered saline or normal human urine with added human serum albumin or human serum, or urine from individuals with nephrotic syndrome. Principal method groups were: turbidimetry (57%), dye binding (25%) and biuret (15%). For all surveys, overall between-laboratory agreement was poor (CV 22 · 8% to 57 · 1%), with ranges of results from 24-fold (0 · 83–20 g/L) to 366-fold (0 · 05–18 · 3 g/L); there was no improvement with time. The most popular method (sulphosalicylic acid turbidimetry) consistently performed the worst, and performance of the direct biuret procedure was also unacceptable; both methods should be discontinued. There were no significant differences in performance between the other major method groups, and none can be specifically recommended. Within the individual calibrant groups, least variation was observed with human serum. A common calibrant for all participants yielded significantly better between-laboratory agreement for all methods except sulphosalicylic acid turbidimetry.
Measurement of Malondialdehyde in Plasma by High Performance Liquid Chromatography with Fluorimetric Detection
Authors: Young I S , Trimble E R
Published: February 2014

The thiobarbituric acid test for malondialdehyde is widely used as an indicator of lipid peroxidation and free radical activity. We describe a simple and sensitive high performance liquid chromatographic (HPLC) method for measuring the malondialdehyde-thiobarbituric acid adduct using fluorimetric detection. Extraction into organic solvent or other complex sample preparation is not required and the assay is sensitive to <0 · 05 μmol/L. This method could easily be applied to any setting where a measure of lipid peroxidation is required.
A Case of Transient Hyperphosphatasaemia of Infancy Associated with a Probable Allergic Disorder
Authors: Tanishima Kiyoh , Ying Qiao , Hashimoto Takuma , Nagata Mitsuko , Matsubara Fujitsugu , Miyawaki Toshio
Published: February 2014

Serum alkaline phosphatase (ALP) activity was found to be grossly elevated (8594 U/L) in a 2-year-old female child, returning towards normal during the subsequent 2 months. Electrophoresis revealed two bands of ALP activity; isoenzyme analysis identified the cathodic band as being of bone origin and the anodic band as sialylated liver ALP. Whilst the aetiology of transient hyperphosphataemia remains unclear a probable allergic disorder appears to be a contributory factor in this patient.
Uniform Requirements for Manuscripts Submitted to Biomedical Journals
Authors:   International Committee of Medical Journal
Published: February 2014

In the 12 years since it was first published the ‘Uniform requirements for manuscripts submitted to biomedical journals’ (the Vancouver style) has proved popular with both authors and editors; over 400 journals have stated that they will consider manuscripts that conform to its requirements and we know that many more do so. The fourth edition, reproduced here, incorporates recent amendments made by the group.
The Determination of Oxalate in Urine and Plasma by High Performance Liquid Chromatography
Authors: Fry Ian D R , Starkey Bryan J
Published: February 2014

We describe a simple, sensitive assay for oxalate in urine or plasma. Acidified urine is pretreated by dilution with neutral phosphate buffer and passage through a C18 cartridge. Stabilized plasma is diluted with neutral acetate buffer and oxalate extracted using a strong anion exchange cartridge. Treated samples are applied to an ion-paired chromatographic system and oxalate detected electrochemically. Recovery of oxalate from augmented samples exceeded 97% from both urine and plasma. Within- and between-assay coefficients of variation assessed at three concentrations were, respectively, better than 4·1% and 8·4% for urine and 3·9% and 5·2% for plasma. The reference range for urinary oxalate excretion is 109–497μmol/24 h. The range for plasma oxalate concentration is 0·6–2·8μmol/L or 0·7–3·9μmol/L after an overnight fast or without dietary restriction, respectively. Urine and plasma oxalate concentrations from this method, gave correlation coefficients (r) of 0·97 and 0·98, respectively, when compared with those from established oxalate oxidase based assays.
Apolipoprotein E Phenotyping: A Word of Caution
Authors: Wenham Philip R , Sedky Alyaa , Spooner Richard J
Published: February 2014

Using two different techniques, phenotyping and genotyping, we have studied allelic variation at amino acids 112 and 158 of the apolipoprotein E gene locus in 52 patients with insulin-dependent diabetes and in 58 non-diabetic controls. Phenotypes were determined by isoelectric focusing and immunoblotting of delipidated, neuraminidase-treated plasma. Genotypes were determined by using the polymerase chain reaction to amplify a 227 base pair fragment of the apolipoprotein E gene spanning both allelic sites. This was then digested with the restriction endonuclease CfoI and the alleles identified by Polyacrylamide gel electrophoresis. Discrepancies between phenotype and genotype were observed in 16 (15%) of the individuals studied, 7 (13%) in the diabetics and 9 (17%) in the controls. From these results it is concluded that isoelectric focusing can lead to the erroneous assignment of apolipoprotein E phenotype even after pretreatment with neuraminidase. It is suggested that genotyping by DNA analysis is the method of choice in determining apolipoprotein E status.
Collection and Storage of Capillary Blood in Glass Fibre Filters for Glycated Haemoglobin Measurement by a Microcolorimetric Method
Authors: Ng M L , Sazali B S , Khalid B A K
Published: February 2014

A filter method for collection and storage of capillary blood spots for glycated haemoglobin (gHb) has been developed. Glass fibre filters (GFB) impregnated with 0·8 M boric acid were used to collect and store capillary blood. Haemoglobin from the dried blood spots was eluted into water and determined by Drabkin's method, while gHb in the eluates was determined by the microcolorimetric method. The intra-assay coefficients of variation (CVs) were 4·5, 4·5 and 3·1% at 882, 1101 and 1704 pmol HMF/mg Hb, respectively. The corresponding inter-assay CVs were 8·6, 8·6 and 6·3 %, respectively. A total of 63 paired capillary and venous blood samples were measured by both the direct and GFB method. The GFB method showed excellent correlation with the direct method ( r=0·948 and r=0·994) after 7 and 14 days' storage at room temperature. The GFB method will enable prior collection and postage of blood samples by patients.
Plasma and Serum Von Willebrand Factor Antigen Concentrations in Connective Tissue Disorders
Authors: Blann A D , Hopkins Julie , Winkles J , Wainwright A C
Published: February 2014

Concentrations of serum and plasma von Willebrand factor antigen were measured in over 200 patients with a variety of connective tissue diseases, and in control samples from over 200 asymptomatic individuals. This comprehensive study found the highest concentrations of von Willebrand factor antigen in patients with vasculitis, Sjögren's syndrome, Felty's syndrome, giant cell arteritis and polyarteritis nodosum. Raised values were also found in rheumatoid arthritis, systemic lupus erythematosus, polymyalgia rheumatica, systemic sclerosis, Raynaud's syndrome, Takayasu's arteritis and Wegener's granulomatosis, but not in oesteoarthritis. It is possible that the difference in von Willebrand factor antigen concentrations in two sub-groups of systemic necrotising arteritis (Wegener's granulomatosis and polyarteritis nodosum) may imply different disease processes. The large numbers involved have allowed us to confirm or question smaller studies of the role of this molecule in connective tissue disease.
Adapting the Uricase/Peroxidase Procedure for Plasma Urate to Reduce Interference Due to Haemolysis, Icterus or Lipaemia
Authors: Leary N O , Pembroke A , Duggan P F
Published: February 2014

The estimation of serum urate by uricase/peroxidase procedures involving single point bichromatic absorbance monitoring gives inaccurate results with samples which are haemolysed, icteric or lipaemic. These inaccuracies can be greatly minimized by reducing the rate of chromogen formation and applying the assay in a kinetic mode.
Body Space Measurements in the Hyponatraemia of Carcinoma of the Bronchus: Evidence for the Chronic ‘Sick Cell’ Syndrome?
Authors: Southgate H J , Burke B J , Walters G
Published: February 2014

Body space measurements using simultaneous multiple isotope dilution techniques were made in both hyponatraemic and normonatraemic patients with carcinoma of the bronchus and wasting, and compared with those in a group of normal volunteers. Both groups of patients showed osmolal loss from cells. The significance of these findings in relation to the development of hyponatraemia is discussed.
Assessment of Micral-Test Microalbuminuria Test Strip in the Laboratory and in Diabetic Outpatients
Authors: Jury Denis R , Mikkelsen Donald J , Glen Deborah , Dunn Peter J.
Published: February 2014

We have evaluated a semi-quantitative dry immunochemical screening method (Micral-Test) for the detection of low concentrations of albumin in urine.

The stability of Micral-Test strips on storage was good, especially with regard to temperature, light and humidity. Changes in urine osmolality (urea and creatinine concentration), pH and sodium and potassium concentration did not have a significant analytical effect on the Micral-Test measurement; extremes of temperature altered the rate of colour development. The depth of dipping the strip into the sample and the timing of reading colour development were critical.

We measured the albumin concentration in 184 urine samples from diabetic outpatients by the Micral-Test and by our in-house immunoturbidimetric method; a Micral-Test result of 20 mg/L had a sensitivity of 91% and specificity of 97% to predict a discriminating urine albumin concentration > 30 mg/L by the in house method.

The Micral-Test is suitable for use by non-laboratory personnel and is capable of producing analytically acceptable results for use in diabetes clinics and by general practitioners.
Development and Evaluation of a Kinetic Diacetyl Monoxime Method for Urine Urea
Authors: Barbour Heather M , Welch C
Published: February 2014

A kinetic assay for urine urea which employs the reaction with diacetylmonoxime at 37°C and undiluted urine was developed. Reaction conditions were optimized using the Monarch centrifugal analyser to produce an assay with the linearity to 450 mmol/L urea, and CVs of 2·3% and 2·5% within-batch and 4·6% and 3·3% between-batch at urea concentrations of 75·9 and 162·7 mmol/L, respectively; recoveries of 98·5% to 99·5% were obtained with the addition of the equivalent of 95 and 190 mmol/L urea. Comparisons were made with one urine urea method employing diacetylmonoxime with dialysis and two enzymatic methods which all involve a sample pre-dilution stage. The urine samples used for the method comparisons did not contain preservatives. However, a range of urine preservatives and a selection of possible interfering metabolites were shown to have no significant effect on the recovery of urea in the assay.
Organic Acids Interfere in the Measurement of Carbon Dioxide Concentration by the Kodak Ektachem 700
Authors: Rifai Nader , Hyde John , Iosefsohn Mariet , Glasgow Allen M. , Soldin Steven J
Published: February 2014

A significant discrepancy was noted in our laboratory between the total plasma carbon dioxide concentration measured by the Kodak Ektachem 700 and the bicarbonate concentration derived from the Corning 170 pH/Blood Gas analyser in an 8-day-old patient. The concentration of total carbon dioxide was 18 mmol/L while the derived bicarbonate was 13 mmol/L. The patient was eventually diagnosed as maple syrup urine disease. This finding led us to examine the effect of various organic acids on the measurement of carbon dioxide by the Ektachem 700. Several interfered significantly. Clinicians should be aware that when organic acid concentrations are increased, the Ektachem 700 total carbon dioxide result may be falsely raised.
Variation of Sweat Sodium and Chloride with Age in Cystic Fibrosis and Normal Populations: Further Investigations in Equivocal Cases
Authors: Kirk J M , Keston M , McIntosh I , Essa S Al
Published: February 2014

Patients attending cystic fibrosis clinics had sweat sodium and chloride concentrations measured, were reassessed clinically and had DNA studies performed. Sweat test results were compared with a matched control population. In both populations sweat sodium increased with age up to 12 years, and did not change significantly thereafter. The age-related increase was significantly less in the cystic fibrosis group. Sweat chloride increased with age in normal, but not in cystic fibrosis children. After age 12 years there was no age-related change in the normal group, and a fall with age in the cystic fibrosis group. Sweat chloride provided the best discrimination between normal and cystic fibrosis populations and this was particularly important in older subjects. Combining sweat sodium and chloride results did not improve discrimination.

Nine patients were identified with equivocal sweat chloride results. DNA studies showed six of these subjects were heterozygous for the ΔF508 mutation in the cystic fibrosis gene. Clinical assessment did not always resolve cases with borderline sweat chloride results.
Serum Urate, Serum Glucose and Diabetes
Authors: Whitehead T P , Jungner I , Robinson D , Kolar W , Pearl A , Hale A
Published: February 2014

We have studied the relationship between serum glucose and urate in 260 699 men and 214 118 women from Sweden, and 140 084 men and 30 653 women from the UK. We found an increase in mean serum urate with increasing glucose concentrations up to 7·0 mmol/L in men and 9·0 mmol/L in women. Thereafter increasing glucose values were accompanied by a statistically significant decrease in urate concentrations. This fall was particularly marked in younger subjects. We believe this may have important implications for the free radical status of diabetics.
Measurement of Dopamine, HVA and HMMA in Untimed Urine Samples: Establishment of Age-Related Reference Data in Children
Authors: Henderson M J , Heney D , McGinlay J M , Lewis I , Bailey C
Published: February 2014

We describe assays for homovanillic acid, hydroxymethylmandelic acid and dopamine that have proven practical and reliable during 3 years of routine use. Homovanillic and hydroxymethylmandelic acids were measured as trimethyl silyl derivatives by capillary gas chromatography. Dilution of samples prior to extraction was found to be necessary to achieve consistent recoveries of these acidic metabolites. Dopamine was assayed by high pressure liquid chromatography with electrochemical detection using an optimized method of catecholamine isolation that involved both ion exchange and alumina extraction. Untimed urine samples were collected from 140 hospitalized children. Age related reference data for the excretion of all three metabolites are reported. We suggest certain precautions that should be observed when using untimed samples and relating the results to creatinine excretion.
A Method for the Determination of Sex Hormone Binding Globulin Using Concanavalin A-Sepharose
Authors: Whittaker J A , Cawood M L , Oakey R E
Published: February 2014

A binding assay for sex hormone binding globulin (SHBG) has been developed in which SHBG is saturated with tritiated dihydrotestosterone (DHT). Separation of bound and free DHT is achieved by using Concanavalin A-Sepharose as a solid phase matrix. The method is described and its performance, including linearity, imprecision and comparison with other methods, is assessed. The assay is simple and robust and is suitable for analysis of samples of plasma or serum for clinical or research use.
A Reference Preparation of Human Prostatic Acid Phosphatase: Purification, Characterization and Field Trials
Authors: Francis J M , Moss D W , Colinet Elisabeth , Calam D H , Bullock D G
Published: February 2014

Acid phosphatase has been prepared in an apparently pure state by affinity chromatography from human prostatic tissue. When dissolved in an acidic albumin solution, lyophilized and stored at −20°C for up to 2 years, no time-dependent loss of catalytic activity was detectable in the reconstituted material. Accelerated degradation tests also predicted complete stability. A preliminary distribution of the lyophilized preparation to 143 laboratories confirmed its robustness and demonstrated its potential usefulness as a calibrant to unify the results of different methods of measuring acid phosphatase activity.
Creatine Kinase Isoforms: Investigation of Inhibitors of in Vitro Degradation and Establishment of a Reference Range
Authors: Davies J , Reynolds T , Penney M D
Published: February 2014

The in vitro stability of creatine kinase isoforms was examined by separation with high voltage electrophoresis. The effect of inhibitors of carboxypeptidase was evaluated. Preservation of samples is essential to inhibit in vitro changes in isoform pattern. EDTA at a final concentration of 15 mmol/L is recommended. Using appropriately preserved samples, normal reference intervals for the MM isoforms have been established.
Carbamylated Haemoglobin in Normal, Diabetic and Uraemic Patients
Authors: Kwan Jonathan T C , Carr Edwin C , Barron Jeffrey L , Bending Michael R
Published: February 2014

Carbamylated haemoglobin arises from the non-enzymic modification of haemoglobin monomers by isocyanate derived from the spontaneous dissociation of urea. We measured carbamylated haemoglobin by high performance liquid chromatography in healthy subjects, non-uraemic hospital patients, diabetics, and different groups of uraemic patients. Carbamylated haemoglobin levels were found to be raised in uraemic subjects, but were independent of age, sex, glycaemic state and haemodialysis procedure. There was no significant difference in carbamylated haemoglobin levels between two groups of patients having different modes of dialysis treatment, probably indicating a similar degree of uraemic exposure in these patients.
Achieving Consensus on Out-of-Hours Laboratory Tests
Authors: McKee Martin , Priest Patricia , Ginzler Maria , Black Nick
Published: February 2014

Many reports on guidelines for investigation describe either the guidelines themselves or their implementation. Implicitly these assume that there has been general agreement about the guidelines, whereas there may be uncertainty about the appropriateness of a particular investigation in a given situation. We report the use of a technique for developing guidelines which explicitly seeks to identify areas of agreement and disagreement, and focuses on the reasons that particular decisions were made and the causes of disagreement.