bluuebunny/crossref_metadata_2025 huggingface dataset:
Dealing with Specimen Problems in a Computerised Clinical Chemistry Laboratory
Authors: Jomain Patricia A. , Owen J. A.
Published: February 2014

The use of a laboratory computer system to deal with specimen problems is described. Problems such as ‘insufficient material’ or ‘haemolysis’ are entered by reception staff or by bench workers so that resolution of the problem will not be overlooked; problems are then listed and dealt with by the duty biochemist. Specimens on printed worksheets are annotated ‘urgent’ where appropriate. Results obtained on-line, which are above top standard, automatically cause the specimen to reappear on the next worksheet marked ‘dilution required’. Data relating to its use over a three-month period are presented together with some comments on the causation of specimen problems and their prevention.
Effect of Anticonvulsant Drugs on Urinary Excretion of γ-Glutamyl Transferase in Women
Authors: Landon M. J. , Bates D. , Kirkley Maureen , Venables G.
Published: February 2014

Excretion of γ-glutamyl transferase was found to be significantly higher in a group of epileptic patients on long-term anticonvulsant therapy than in normal subjects. The losses, which may reflect renal enzyme induction, were unrelated to drug dose or duration of therapy and were significantly lower than those found in normal healthy pregnant women at term.
Serum Deoxycytidylate Deaminase Activity after Myocardial Infarction
Authors: Roberts R. G. , Davies A. G. , Jones D. D.
Published: February 2014

The activity of serum deoxycytidylate deaminase, not hitherto reported to increase after myocardial infarction, has been investigated and the results have been related to other cardiac enzymes, including the MB fraction of creatine phosphokinase. Deoxycytidylate deaminase was found to increase to maximum activity on the third day after infarction. It may therefore be added to the list of ‘cardiac enzymes’.
Distribution of Gold in Blood during Chrysotherapy
Authors: Francois P. E. , Goldberg I. J. L. , Lawton K. , Al-Ani D. T. , Redding J. H.
Published: February 2014

Measurements have been made using electrophoresis and neutron activation analysis of the distribution of gold in the blood of four patients who have responded well to chrysotherapy for rheumatoid arthritis. It has been shown that in these patients there is little, if any, binding to the fibrinogen. The majority of protein-bound gold is associated with the albumin but significant amounts are bound to the other proteins. There is a small amount of gold associated with the blood cells.
Enzyme Multiplied Immunoassay of Phenytoin and Carbamazepine Using the Centrifichem Analyser
Authors: Mulligan Fiona A. , Fleetwood J. A. , Smith P. A.
Published: February 2014

Procedures for the enzyme multiplied immunoassay of phenytoin and carbamazepine using the Centrifichem centrifugal analyser are described. Within-batch, between-batch, and between-day precision are reported. Accuracy is assessed by recovery experiments. The technique is compared with gas-liquid chromatography in the analysis of a number of human serum samples containing a range of concentrations of the drugs.
Development and Validation of a Specific Radioimmunoassay for Somatostatin in Human Plasma
Authors: Penman Erica , Wass J. A. H. , Lund Alison , Lowry P. J. , Stewart Jennifer , Dawson A. M. , Besser G. M. , Rees Lesley H.
Published: February 2014

Little is known about the factors controlling somatostatin secretion in man, and data are not available on the changes in circulating levels in various human physiological or pathophysiological states. This is mainly a consequence of the technical difficulties involved in measuring somatostatin in plasma. In the presence of plasma, binding of somatostatin tracer to antibody was consistently decreased by about 20%, and this could not be abolished by the addition of EDTA and aprotinin or by the use of specially prepared somatostatin-free plasma. Furthermore, in the presence of plasma, endogenous somatostatin does not dilute in parallel with synthetic cyclic somatostatin standard.

We have, therefore, developed and validated a radioimmunoassay for somatostatin using prior extraction of the peptide onto leached silica glass. Tyrosine-11 somatostatin was iodinated using lactoperoxidase and purified on ODS silica. This method is superior to iodination using chloramine-T with CMC cellulose purification, and gives a highly purified preparation with a shelf-life of at least eight weeks. Using this tracer and a specific antiserum, the limit of sensitivity of the assay was 10 pg/ml, with an intra-assay coefficient of variation of 12% (n = 16) and inter-assay coefficient of variation of 15% (n = 10). Parallelism has been demonstrated between standard synthetic cyclic somatostatin and all extracted plasma samples. The mean recovery of exogenous somatostatin from plasma was 78%.

The fasting level of immunoreactive somatostatin at 0900 hours in 40 normal subjects ranged from 17 to 81 pg/ml. Care is needed, however, when comparing these values with those obtained from other laboratories since standard preparations of somatostatin vary considerably in their immunopotency.
A Data Processing System for a Group of Three Clinical Chemistry Laboratories; 1. Hardware and Organisation
Authors: Hirst A. D. , Naylor D. , White H. L. , Walter M.
Published: February 2014

A real time data processing system for a group of three clinical chemistry laboratories (one base and two satellite) has been developed as a successor to one used previously. This paper describes both the inadequacies of the previous worksheet-based system and the advantages of the new system, including flexibility, fast response and comprehensiveness, incorporating urgent routine and long delay (that is, endocrine) requests, and the use of a parallel flow work scheme.
A Data Processing System for a Group of Three Clinical Chemistry Laboratories; 2. File Structure and Operation
Authors: Naylor D. , White H. L. , Walter M. , Hirst A. D.
Published: February 2014

In the preceding article the hardware and organisation of a new data processing system were described. This paper deals with the file structure and operation, the use of management information, the economical use of disc-file space and hardware, and the transferability of the system.
Routine Laboratory Investigation of Urinary Catecholamine Metabolites in Sick Children
Authors: Niehaus C. E. , Ersser R. S. , Atherden Sheila M.
Published: February 2014

Simple and rapid thin-layer chromatographic methods have been used to investigate the catecholamine metabolites present in the urine of sick children. A semi-quantitative method for 4-hydroxy-3-methoxy-mandelic acid (HMMA) has been devised and compared with the quantitative spectrophotometric procedure. The methods have been performed on both normal subjects and children with catecholamine-secreting tumours, without dietary restriction, and have led to a 50% reduction in the number of samples requiring laborious quantitative determination of HMMA excretion.
Dilution Effect on Serum Creatine Kinase in Carriers of Duchenne Muscular Dystrophy
Authors: Simpson A. C. , Holmes D. , Pennington R. J. T.
Published: February 2014

Dilution of serum before assay consistently increased the activity of serum creatine kinase both in normal female subjects and in carriers of Duchenne muscular dystrophy.
An Evaluation of Serum Thyroxine Binding Globulin as a Routine Test of Thyroid Function
Authors: McDowell David R.
Published: February 2014

Serum thyroxine binding globulin (TBG) values were correlated with other thyroid function test results and with the clinical condition in 680 patients. The estimation of serum TBG was helpful in the evaluation of thyroid status only in those patients who were either acutely ill, were taking the contraceptive pill, or were pregnant. Further, the derived index, thyroxine: TBG ratio, proved to be a better diagnostic index than the thyroxine: tri-iodothyronine uptake ratio and in many cases would have avoided the use of more expensive and time-consuming tests.
Screening for Cushing's Syndrome using Early Morning Urine Samples
Authors: Walker Michael S.
Published: February 2014

Urinary free 11-hydroxycorticosteroid/creatinine ratios (UFC/Cr) were determined in early morning urine samples from 138 obese subjects attending endocrine clinics in the Glasgow area. The majority of patients (128) had UFC/Cr ratios within the normal range for non-obese subjects (5–55 μmol/mol). Of those with elevated UFC/Cr ratios, further investigations of the hypothalamic-pituitary-adrenal axis confirmed a diagnosis of Cushing's syndrome due to bilateral adrenal hyperplasia in six of the cases and adrenal tumours in a further two patients. In the remaining two patients there was evidence of intermittent adrenal hyperactivity with inconsistent responses to insulin-induced hypoglycaemia tests.
Re-Examination of Effect of Paracetamol on Serum Uric Acid Measured by Phosphotungstic Acid Reduction
Authors: Smith M. , Payne R. B.
Published: February 2014

The drug paracetamol ( N-acetyl- p-aminophenol; acetaminophen) caused a spurious increase in serum uric acid measured by phosphotungstic acid reduction methods. However, the increase was less than 0·12 mmol/l at plasma levels of paracetamol found in overdosage (40 mg/100 ml) and was small at therapeutic concentrations (less than 4 mg/100 ml). It is concluded that few patients with joint pain who have taken paracetamol as an analgesic will have clinically misleading values for serum uric acid.
A Simple Micromethod for 25-Hydroxyvitamin D Estimation
Authors: Fairney Angela , Turner C. , Hanson S. , Zambon Mary
Published: February 2014

A quick and simple method for estimating 25-hydroxyvitamin D is described. It involves dichloromethane extraction followed by competitive protein-binding assay without chromatography. This assay can be performed on 100 μl of serum and enables 50 samples to be estimated in one working day. The simplicity, speed, and sample size of this method make it very suitable for use in a routine clinical biochemistry laboratory. It is particularly useful when calcium disorders secondary to abnormalities in vitamin D intake and metabolism are suspected.
Reliability of Serum Ferritin Determinations after Total Dose Infusion of Iron Dextran in Pregnancy
Authors: Lappin T. R. J. , Whiteley Linda A. , Murnaghan G. A.
Published: February 2014

Serum ferritin, serum iron, total iron binding capacity, and haemoglobin levels were measured in a group of 36 pregnant women before, one week after, and four weeks after a total dose infusion of iron dextran (T.D.I.). The serum ferritin level is considered to provide a reliable index of maternal iron stores one month, but not one week, after TDI.
Quality Control of Radioimmunoassays for Proteins: The First Two and a Half Years of a National Scheme for Serum Growth Hormone Measurements
Authors: Hunter W. M. , McKenzie I.
Published: February 2014

The philosophy and achievements of the first two and a half years of a national quality control scheme for serum growth hormone assays are described. Three serum samples were distributed to participating laboratories every two weeks. A computer-produced summary of the quality control results, which contained scattergrams and a statistical analysis, was returned to participants four weeks after despatch. The performance of 11 experienced (SAS) laboratories was found to fulfil the necessary accuracy criteria, and their results provided the ‘reference group mean’, which served as the target value. Gross positive bias exhibited by several laboratories was due to the use of assays with inadequate sensitivity, and this practice was eliminated during the first six months. During the course of the Scheme the average bias fell from 30 to 14%. With assays of adequate sensitivity, bias was almost invariably due to the misuse of standards. Median within-laboratory, between-batch precision (CV) improved from 23 to 15%. The best performers achieved between-batch CV of 7% which was 1·5 × their within-batch CV: the worst had three- to four-fold differences between within- and between-batch CV. Rudimentary quality control of interpretation was found to result in improvements in interpretation per se and also served to reinforce the desire to improve numerical agreement.

A ‘recommended procedure’ based upon supplied first and second antibody, and a communal ‘reference range’ from 280 untreated acromegalics, both proved valuable.
Abnormal Keratan Sulphate Excretion
Authors: Longdon K. , Pennock C. A.
Published: February 2014

Simple methods for the detection of keratan sulphate in urine have been applied to over 300 urine samples collected from children and adults with bone and cartilage dysplasias with or without mental retardation. Abnormal keratan sulphate excretion, which is a feature of type IV mucopolysaccharidosis (Morquio syndrome), is found in patients with that condition only during childhood. Abnormal excretion is also a feature of Kniest dysplasia and GM1 gangliosidosis and may be present in a number of other bone and cartilage dysplasias of unknown aetiology.
Specific Methods for the Determination of Radioactivity in D-(—)-3-Hydroxybutyrate in Blood Plasma
Authors: Emmanuel B. , Stangassinger M. , Giesecke D.
Published: February 2014

Two simple, high-yield rapid methods with good reproducibility are described, which permit the determination of radioactivity in plasma D-(—)-3-hydroxybutyrate. The compound is converted to acetoacetate, using a modified enzymatic method. In procedure 1, acetoacetate is reacted with 2, 4-dinitrophenylhydrazine; the resulting hydrazone is oxidised by means of a sample oxidiser, and the product 14CO2 is collected in scintillation liquid and counted. In procedure 2, a Conway microdiffusion unit is applied. The acetoacetate is decarboxylated to acetone in the presence of o-phenylenediamine, and the acetone is then diffused into semicarbazide solution. This solution, containing the semicarbazone derivative of labelled acetone, is transferred to liquid scintillation and counted. In both procedures the radioactivity is measured simultaneously in a separate sample which was not subjected to the enzymatic conversion of D-(–)-3-hydroxybutyrate. The difference in radioactivity between the two samples is attributed to labelled D-(–)-3-hydroxybutyrate.
Temporal Changes in the Concentrations of Serum Constituents in Healthy Men
Authors: Harris Eugene K. , Brown Stanley S.
Published: February 2014

The distributions of within-person variances in the concentrations of 10 commonly assayed serum constituents have been derived from data on 37 healthy male subjects studied at weekly intervals over a period of five months. All 10 distributions appear to be of log-normal form. The relevance of the findings to the interpretation of differences between serial measurements in a given individual is discussed. Examples are given to show how the information on within-person variances for a particular analyte, organised into a simple graph, may be used to test medical opinions on threshold values for serial changes in the concentration of this analyte in a given individual. In this way, biological variability as well as analytical error may be taken into account quantitatively when assessing the significance of a difference between two serial measurements.
Is the L/S Ratio Really a Lecithin/Sphingomyelin Ratio?
Authors: Duck-Chong Coral G. , Brown Louise M.
Published: February 2014

Fetal lung maturity is commonly assessed by determining the ratio of lecithin/sphingomyelin in centrifuged amniotic fluid. In a variety of chromatographic systems currently used for the routine determination of the lecithin/sphingomyelin ratio, including the systems recommended in the original procedure, at least one and frequently two additional phospholipids, normally present in amniotic fluid, tend to chromatograph between or overlapping with lecithin and/or sphingomyelin. These phospholipids have been tentatively identified as phosphatidylserine and phosphatidylinositol. The extra phospholipids contribute significantly to the routine lecithin/sphingomyelin ratio with considerable variation between individual cases. Treatment of dried lipid extracts with cold acetone before chromatography, as suggested in the original lecithin/sphingomyelin ratio procedure, does not remove the interfering phospholipids.
Accuracy of Serum Anticonvulsant Measurements
Authors: Berchou R. C. , Lodi R. A. , Sherman J. A.
Published: February 2014

An enzyme multiplied immunoassay technique is compared with a gas-liquid chromatographic technique for the measurement in blood serum of the anticonvulsants phenytoin, carbamazepine, phenobarbitone, primidone, and ethosuximide. The correlation between results obtained by each method was excellent, and both systematic and random errors were well within acceptable limits.
Use of Sodium Salicylate as a Blocking Agent for Cortisol-Binding-Globulin in a Radioimmunoassay for Cortisol on Unextracted Plasma
Authors: Kane J. W.
Published: February 2014

This report describes investigations into the use of sodium salicylate as a cortisol-binding-globulin blocking agent and the subsequent development of a radioimmunoassay for cortisol on unextracted plasma. Cortisol antiserum was raised against a cortisol 3–0-(carboxymethyl) oxime-bovine serum albumin conjugate. A 125I-labelled cortisol-tyrosine methyl ester conjugate was also prepared for use in the assay. The radioimmunoassay developed involved no pre-treatment or extraction of the samples before analysis and was extremely simple to perform. Comparison with another radioimmunoassay for cortisol and with the Mattingly fluorimetric assay gave good correlation.
A Simple Procedure for the Determination of Carbamazepine in Plasma by High Pressure-Liquid Chromatography
Authors: Johnston C. K. , Lester G. H.
Published: February 2014

We describe a simple, rapid procedure for the estimation of carbamazepine in plasma. Protein is precipitated, and extraction is achieved by the addition of acetonitrile containing the internal standard N-acetyltryptophan ethyl ester. Separation is by reverse-phase high-pressure liquid chromatography with an acetonitrile: water mobile phase, and detection is by UV absorption at 280 nm. Total retention time is less than 7 minutes. Initial results gave within-batch and between-batch coefficients of variation of less than 2 %, and mean recovery of 97 %. The method is free from interference by other common anticonvulsant drugs.
Successful Operation of a Regional Scheme for the Maintenance of Automatic Analysers
Authors: Wyper D. J. , Porter D. , Etchells A. H. , Fleck A. , Kenny A. P. , McLelland A. S.
Published: February 2014

The main operational and financial aspects of the maintenance service provided by the West of Scotland Health Boards' Department of Clinical Physics and Bio-Engineering (DCPB) to the clinical chemistry laboratories in the region are described. The scheme, in operation since March 1976, covers all breakdown servicing and engineering preventive maintenance for Technicon Auto-Analyzer equipment valued at £1¼ million in terms of direct replacement costs. The engineering team works closely with the laboratory staffs to ensure that the performance of the equipment is maintained to specification. The direct economies for the Health Boards through savings in maintenance contract charges total around £60 000 per year. In addition, considerable sums have been saved by servicing, modifying, and constructing other instruments for the laboratories outwith the immediate remit of Technicon maintenance. Other economic and operational benefits which result from the scheme are commercially disinterested advice on equipment obsolescence and replacement, and redistribution between the laboratories of old but useful equipment to meet specific needs of the service in the region.
An Improved Radioenzymatic Assay for Histamine in Human Plasma, Whole Blood, Urine, and Gastric Juice
Authors: Bruce C. , Taylor W. H. , Westwood A.
Published: February 2014

A radioenzymatic method suitable for the assay of histamine in human blood, urine, plasma, and gastric juice is described. It differs from earlier methods by use of a histamine methyltransferase preparation from pig brain, of high activity tritiated S-adenosylmethionine, and of a heat precipitation step to reduce the previously noted interference from plasma constituents. The method is simpler than those requiring solvent extraction and concentration of histamine, gives recoveries in the range 80–120%, and so eliminates the need for internal standardisation. The method is sensitive and precise with coefficients of variation for blood, urine, and plasma of 5%, 6%, and 13% respectively. The mean ± standard deviation for normal human plasma histamine is 5 ± 4 nmol/l, for whole blood 559 ± 193 nmol/l, and for urine 229 ± 128 nmol/24h.
Alkaline Phosphatase Activity in Lyophilised Quality Control Serum
Authors: Bullock D. G. , McSweeney F. M. , Saidi H. , Whitehead T. P.
Published: February 2014

The rise in alkaline phosphatase activity has been studied after reconstitution of 16 commercial preparations of lyophilised quality control material. The effects of storage temperature and analytical method on the rise in activity have also been studied, with a view to producing a reconstitution protocol suitable for recommendation to participants in external quality control surveys. Great differences were found in the magnitude of this rise in activity; these differences can be reduced to negligible levels if the material is mixed for 30 minutes at ambient temperature after reconstitution and then stored for not more than 4 hours at 4°C before assay.
Thyroid Function Tests in Thyroxine-Binding Globulin Deficiency
Authors: Cusick C. F.
Published: February 2014

Results are presented on two patients with complete and two with partial thyroxinebinding globulin (TBG) deficiency. All four subjects had lowered serum thyroxine but were clinically euthyroid. While thyroid hormone uptake tests or TBG assay were effective in the recognition of such individuals, indices based on these tests were misleading in assessing their thyroid status. Results within the reference range were obtained with the Immophase Free Thyroxine assay.
Separation of Creatine from Arginine in Biological Fluids by Thin-Layer Chromatography
Authors: Datta Shompa , Datta Salil C.
Published: February 2014

Creatine in biological fluids was estimated using a modified Sakaguchi procedure. Interference by arginine was eliminated by thin-layer chromatography.
Quantitative Recovery of Alkaline Phosphatase and γ-Glutamyl Transferase Isoenzymes after Polyacrylamide Gel Electrophoresis
Authors: Brooks TJ , Sammons HG
Published: February 2014

Loss of activity of the isoenzymes of γ-glutamyl transferase and alkaline phosphatase has been shown to occur during electrophoresis on polyacrylamide gel. After studying the possible factors concerned in this loss, reasonable recovery from the gel can be obtained only for the isoenzyme staying at the origin. Maximum recovery is 60% for origin γ-glutamyl transferase and 92% for origin alkaline phosphatase.
A Rapid Solid-Phase Radioimmunoassay for Human Plasma Follicle-Stimulating Hormone
Authors: Lovesey AC
Published: February 2014

The measurement of plasma levels of human follicle-stimulating hormone (FSH) has proved to be of value for the study of the hypothalamic-hypophyseal-gonadal axis, greatly facilitating the diagnosis and management of problems relating to the menopause and infertility. In the present work a solid-phase radioimmunoassay for human FSH has been developed. This system is characterised by high precision, is economical, and is considerably faster to operate than conventional double antibody systems used in the hospital assay service. Reference values for plasma FSH in various endocrine states are recorded and discussed.
An Improved Colorimetric Method for the Determination of Plasma Paracetamol
Authors: Archer Choo T , Richardson RA
Published: February 2014

The commonly used nitration colorimetric method for urgent paracetamol estimation suffers from interference by salicylates and salicylamide. This communication describes a simple modification which eliminates this interference without affecting either the recovery or precision of the method. The results obtained were briefly compared with those obtained by an established gas chromatographic procedure.
Introduction of Computer Facilities to a Clinical Chemistry Laboratory
Authors: Morgan Leo M , McConnell Greg , Chandler Edward , Welshman S Gordon
Published: February 2014

A clinical chemistry laboratory information system based on MUMPS is described, together with the problems associated with its implementation. Tabular displays and cusum charts as well as cumulative records are available on a real-time basis. Data capture is by both on-line and off-line techniques. After 18 months' live running the management of information within the laboratory has been significantly improved.
Outlying Values in the National Quality Control Scheme
Authors: Healy MJR , Whitehead TP
Published: February 2014

A modified statistical method for the detection of outlying values has been applied to five fortnightly sets of data from the National Quality Control Scheme. The overall outlier rate was 2·4 %, not varying greatly between analytes. Many of the outliers appear to be due to sample identification errors.
Experiences with a Regional Quality Control Scheme for Salicylate and Paracetamol over a Period of Two Years
Authors: Wiener K
Published: February 2014

The organisation of a regional quality control scheme for salicylate and paracetamol estimations in plasma is described. The results show considerable variation in both bias and precision between laboratories, with some overall improvement in performance during the second year of the scheme. No method can be singled out as producing better results than the others. The major factor seems to be the care with which the analyses are performed.
Solid Phase Enzyme Immunoassay of Human Plasma Follicle Stimulating Hormone
Authors: Lovesey AC
Published: February 2014

A novel, solid phase, enzyme immunoassay for the measurement of human plasma follicle stimulating hormone has been developed. The method is a direct, competitive inhibition system of high precision and accuracy. It compares favourably with solid phase radioimmunoassay using the same antiserum and hormone preparations. Hormone reference values are presented for normal men, and for women at various stages in the menstrual cycle and in the menopausal state.
An Assessment of a Microcolumn Chromatographic Method for the Measurement of Haemoglobin A1
Authors: Baumgart R , France MW , Uaconaill D , Murnaghan S , Pereira M , Drury MI
Published: February 2014

A microcolumn method for the measurement of haemoglobin A1 (Hb A1) was assessed. The between assay coefficient of variation was less than 4 %. Factors influencing the assay are discussed. Fluoride oxalated blood was found to be unsuitable for Hb A1 assay. Hb A1 in whole heparinised blood was found to be stable for nine days at 4°C and for longer if buffered dextrose was added to the sample. The possibility of artefactual lowering of the Hb A1 value by the selective loss of older red cells was investigated.
Immunoreactive Aldolase C in Cerebrospinal Fluid of Patients with Neurological Disorders
Authors: Willson V J C , Graham J G , McQueen I N F , Thompson R J
Published: February 2014

Nervous-system specific aldolase C has been detected in human cerebrospinal fluid (CSF) by radioimmunoassay. Measurement of 138 samples of CSF showed a mean level of 92 ± 28 ng/ml. There was no correlation between the level of CSF aldolase C and the CSF total protein, albumin, IgG, or IgA levels. Aldolase C immunoreactivity present in concentrated CSF diluted out in parallel with the standard curve in the assay and showed an elution profile on ion-exchange and gel filtration chromatography similar to that of aldolase present in whole human brain extracts. Addition of known quantities of purified aldolase C4 to CSF gave quantitative recovery on subsequent radioimmunoassay. Measurement of aldolase C in the CSF of 66 patients with neurological disorders showed several patients with levels considerably in excess of 120 ng/ml, but there was no statistically significant difference in the mean levels between groups of patients with different diseases.
Programming and Running Radioimmunoassay in the h-TSH Screening Procedure Using Dried Blood Spots and the NE1600 Gamma Counter on Line to the HP9815S Calculator
Authors: Edwards R W H , Hulse J A , Jackson Doreen , Spracklan Anne , Clayton Barbara E
Published: February 2014

Screening for hypothyroidism has been achieved by seeking raised concentrations of thyroid stimulating hormone (h-TSH) in dried blood samples collected on absorbent paper from some 1700 newborn babies each week using double antibody radioimmunoassay and 125I-label counting on a NE1600 gamma counter linked to a HP9815S desk top calculator.

Specificity, accuracy, and quality control of the assay have been investigated. The calculator programme stores all count, time, and calculated data and uses log-log function formation and third-power homoscedastic polynomial fit to the calibration data followed, if necessary, by elimination of outliers set at p= 0·5 %. Branching in the calculation procedure provides the ability to process sample data in subgroups, completely to reprocess data (including presentation in a form suitable for making a histogram plot), and to reset without loss of data in case of instrument or main power failure.

Variance analysis was used to select the minimum duration of count (50 s), and it was demonstrated that homoscedasticity pertains in the regression calculation.
Rapid Determination of Alpha-Fetoprotein in Amniotic Fluid Using an Automated Immunoturbidimetric Technique
Authors: Evans Stuart E
Published: February 2014

A rapid and precise immunoturbidimetric assay for the measurement of alpha-fetoprotein in amniotic liquor has been developed. The method is an ‘end-point’ technique without blank correction since non-specific turbidity does not occur with amniotic liquor. The assay is able to distinguish 4 mg/l from zero and is unaffected by gross blood staining of the liquor. The protocol requires a duplicate analysis of the liquor to detect high levels of alpha-fetoprotein.
A Critical Evaluation of a Serum Seromucoid Assay and its Replacement by a Serum α1 Acid Glycoprotein Assay
Authors: Thaw Patricia A , Albutt Eileen C
Published: February 2014

The composition of serum seromucoid, the protein fraction of serum not precipitated by 0·6 M perchloric acid, has been shown to vary with the technique of preparation. Immunochemical examination revealed that 91·5% of the protein present in the seromucoid fraction of serum was α1 acid glycoprotein, the remainder consisting of α1 antitrypsin, α1 antichymotrypsin, β2 glycoprotein, haemopexin, albumin, and pre-albumin. Serum α1 acid glycoprotein concentration determined by radial immunodiffusion correlated well with serum seromucoid concentration although the former was usually 0·4 g/l lower. The determination of serum α1 acid glycoprotein by an immunological method is more precise than the seromucoid method and is not subject to interference from other proteins.
Flameless Atomic Absorption Spectroscopy of Plasma Chromium
Authors: Thompson David A
Published: February 2014

A flameless atomic absorption spectroscopy method has been developed for the measurement of chromium. Background correction has been modified by recording non-atomic absorption separately from atomic absorption on a double-pen recorder. This was achieved by using the prime spectral line of uranium (358·5 nm, within 0·6 nm of that of chromium—357·9 nm) and was possible only because of the absence of uranium from the plasma samples. Masking of the analytical signal at atomisation by non-atomic absorption was thus eliminated and gave the method a sensitivity of 3 pg and a detection limit of 150 pg/ml. Postprandrial plasma chromium values were measured in 32 insulin-treated diabetics (1·65 ±0·15 ng/ml), in 53 non-insulin treated diabetics (2·05 ± 0·16 ng/ml), and in 144 control non-diabetics (2·00 ± 0·14 ng/ml). The difference between the mean plasma chromium level of the insulin-treated diabetics and both the non-insulin treated diabetics and the control groups was statistically significant (p<0·05).
An Improved Continuous Flow Method for Serum Creatinine Using the Jaffé Reaction
Authors: White W A , Attwood E C
Published: February 2014

A method for the measurement of creatinine is described in which serum is dialysed directly into a combined alkaline picrate reagent. Baseline noise and drift are eliminated, and precision is improved by avoiding the need to add further reagents after dialysis. This may be of particular interest to laboratories that perform this assay on first-generation AutoAnalyzer equipment.
A Rapid Method for the Determination of Perhexiline in Serum Using Gas-Liquid Chromatography
Authors: Cooper J D H , Turnell D C
Published: February 2014

A rapid method for the estimation of perhexiline in serum is presented. The procedure employs a single extraction, and no derivatisation is required. The procedure is linear over the range 0·4–4·0 mg/l, and the limit of detection is 0 09 mg/l. The within- and between-batch coefficients of variation at a concentration of 2·0 mg/l were 2·5 and 41%, respectively. Recoveries over the range 0·4–4·0 mg/l produced a mean of 104%. The method is free from interference by other common drugs used in the treatment of angina.
Micromodification of an Immunoradiometric Assay for Proinsulin
Authors: Sopwith A M , Hales C N
Published: February 2014

A micromodification of an indirect two-site immunoradiometric assay for proinsulin is described. The assay is performed not in tubes but in disposable pipette tips. The volume of sample necessary is reduced from 50–200 μl to 10 μl. This economy is accompanied by economy of reagents. The repetitive washing steps required by each stage of the assay are considerably simplified and speeded. The time needed for completion of the assay has been reduced from 72 to 48 hours. The detection limit of the assay is unaltered at 6 pmol proinsulin/l.
A Comparison of Three Methods of Measuring Serum High Density Lipoprotein Cholesterol in Diabetics and Non-Diabetics
Authors: Durrington Paul N
Published: February 2014

Serum high density lipoprotein (HDL) cholesterol was measured in non-diabetic and diabetic men and women by ultracentrifugation, heparin-manganese chloride precipitation (heparin/Mn++), and sodium phosphotungstate-magnesium chloride precipitation (PT/Mg++). Results of the three methods were closely correlated in both diabetics and non-diabetics. Concentrations were, however, generally lowest by PT/Mg++, intermediate by ultracentrifugation, and highest by heparin/Mn++. These differences were of small magnitude except in the case of diabetic patients treated with insulin. In these patients, serum HDL cholesterol levels were significantly greater than those of non-diabetic patients when measured by heparin/Mn++ and ultracentrifugation, but not by PT/Mg++ This was explained by the finding that the discrepancy between PT/Mg++ and ultracentrifugation increased with increasing HDL cholesterol concentration
Internal Analytical Quality Control Using the Cusum Chart and Truncated V-Mask Procedure
Authors: Edwards R W H
Published: February 2014

It is recommended that quality control data be recorded on a standard form to facilitate calculation of the cusum increments and of the cumulative sums (cusums) for plotting on the cusum chart. The ‘in control’ and ‘out of control’ judgements are made with the aid of a truncated V-mask. Full details of calculation procedures are described without recourse to statistical theory so that the cusum and truncated V-mask procedure may be carried out by operators without training in statistics.
24-Hour Urine Composition of Sri Lankan Adults and Their Response to 100 mg Dihydrochlorothiazide
Authors: Vinayagamoorthy T
Published: February 2014

In the present study, 205 ‘normal hospitalised subjects’ in the age group 16–60 years were included in a clinical trial to estimate the 24-hour urinary composition. Their response to 100 mg dihydrochlorothiazide was also determined. The study revealed that there is a marked difference in the 24-hour urine volume and composition between that observed in the present study and that presented in the modern literature; 100 mg dihydrochlorothiazide was found to produce a significant diuretic and natriuretic effect in normal Sri Lankan adults. There is a very high correlation between the volume of urine and the cations in the basal excretion as well as with the standard diuretic. The coefficient of regression of volume on cations in the basal excretion was found to be less than that with the standard diuretic.
A Recommended Scheme for the Evaluation of Kits in the Clinical Chemistry Laboratory
Authors: Percy-Robb I W , Broughton P M G , Jennings R D , McCormack J J , Neill D W , Saunders R A , Warner Mary
Published: February 2014

A scheme for kit evaluation in the individual clinical chemistry laboratory is presented. Recommendations for assessing accuracy, precision, and stability are included along with a scheme for preparing for the evaluation and writing the final report.
A Procedure for the Redefinition of Equivocal Results in Thyroid Function Tests
Authors: Barnard David J , Bingle John P , Garratt C John
Published: February 2014

A retrospective analysis has been made of patients who had been classified (on the basis of measurements of serum thyroxine and thyroid hormone uptake test) as equivocal thyrotoxic (273 patients) or as equivocal hypothyroid (352 patients). The final diagnosis of these patients has been traced from their medical records. The results illustrate that control groups of euthyroid, thyrotoxic, and primary hypothyroid subjects differ from these equivocal groups. The populations initially classified as equivocal have been used to redefine the combinations of values obtained in the serum thyroxine and thyroid hormone uptake test which must be classed as equivocal. Using this redefinition, it is shown that a number of additional tests had been carried out when it could now be predicted with confidence that no useful new information would be obtained. The procedure described is not limited to tests of thyroid function and could easily be applied in most laboratories to redefine the ranges of results classified as equivocal.
Effect of Platelets on Apparent Leucocyte Ascorbic Acid Content
Authors: Evans Richard M , Currie Lilias , Campbell Allan
Published: February 2014

The leucocyte ascorbic acid content is widely used as a measure of tissue ascorbic acid status. Standard methods of analysis, however, isolate both leucocytes and platelets (buffy layer), with consequent overestimation, since platelet ascorbic acid is attributed to the leucocytes.

Fourteen healthy individuals on ascorbic acid supplements and 11 patients on mega dose ascorbic acid therapy were studied. A significant correlation was demonstrated between the ‘leucocyte’ ascorbic acid content and the platelet: leucocyte ratio (r = 0·70, p<0·001). It is suggested that changes in the relative distribution of platelets and leucocytes in the blood will result in an apparent change in the ‘leucocyte’ ascorbic acid content regardless of any actual change in the ascorbic acid content of the cells.
Quantification of Antibodies against Factor VIII by an Immunonephelometric Method in a Continuous-Flow System
Authors: Malagon F , Elorza F L , Martin E , Jimenez A
Published: February 2014

A new immunonephelometric method is described for the quantification of antibodies against factor VIII in sera from patients suffering from haemophilia A. We have been able to reduce the reaction time to only 16 minutes, which permits its application to emergency cases. Applying Spearman's test, we have correlated the results obtained by the immunonephelometric and Ruggieri's methods, obtaining r = 0·87, p<0·01 for n = 11. From the reproducibility studies we obtained SD = 1·16 as maximum dispersion value. Because it is a fully automated method in a continuous-flow system, the possible manual errors are reduced to a minimum; 60 determinations can be carried out in 1 hour.
Validity of Transcobalamin II-Based Radioassay for the Determination of Serum Vitamin B12 Concentrations
Authors: Paltridge Gulielma , Rudzki Zbigniew , Ryall Richard G
Published: February 2014

A valid radioassay for the estimation of serum vitamin B12 in the presence of naturally occurring vitamin B12 (= cobalamin) analogues can be operated if serum transcobalamin II (TC II) is used as the binding protein. Serum samples that gave diagnostically discrepant results when their vitamin B12 content was analysed (i) by a commercial radioassay known to be susceptible to interference from cobalamin analogues, and (ii) by microbiological assay, were further analysed by an alternative radioassay which uses the transcobalamins (principally TC II) of diluted normal serum as the assay binding protein. Concordance between the results from microbiological assay and the TC II-based radioassay was found in all cases. In an extended study over a three-year period, all routine serum samples sent for vitamin B12 analysis that had a vitamin B12 content of less than 320 ng/l by the TC II-based radioassay (reference range 200–850 ng/l) were reanalysed using an established microbiological method. Over 1000 samples were thus analysed. The data are presented to demonstrate the validity of the TC II-based radioassay results in this group of patients, serum samples from which are most likely to produce diagnostically erroneous vitamin B12 results when analysed by a radioassay that is less specific for cobalamins.
Capillary Gas Chromatographic Measurement of Neutral Urinary Steroids: Evaluation and Comparison with Alternative Methodology
Authors: Phillipou George , Frith R Gordon , James Steve K.
Published: February 2014

The major neutral urinary steroids have been quantitated by capillary gas chromatography and the reproducibility and accuracy of the method have been fully evaluated. Typical intra- and inter-assay coefficients of variation for individual steroids ranged from 4·9 to 10·1% and from 15·6 to 21·5%, respectively. Comparison of steroid values with alternate and commonly employed procedures for measuring urinary 17-oxosteroids, total 17-oxogenic steroids, and cortisol and plasma dehydroepiandrosterone-sulphate yielded correlation coefficients between 0·71 and 0·79. A definite relationship between serum cortisol and urinary trihydroxy-pregnanedione was also shown. Urinary androstenedione metabolites, however, could not be significantly (P>0·05) correlated with the normalised androgen ratio in plasma.
External Quality Assessment of Serum Alpha-Fetoprotein Assays
Authors: Woodhead J S , Kemp Heather A , Nix A B J , Rowlands R J
Published: February 2014

Adequate control of performance in immunoassays of maternal serum alpha-fetoprotein is an essential part of screening for neural tube defects. Information derived from external quality assessment schemes may be of limited value in monitoring individual laboratory performance and stresses the need for proper internal quality control.
Prolactin and Impotence in Diabetes Mellitus
Authors: Lester Eva , Woodroffe F. J. , Smith R L
Published: February 2014

A study was undertaken to determine whether impotence in some diabetic patients might be due to a coincidental prolactinoma and therefore be potentially treatable. Of 83 consecutive men attending a diabetic clinic, three were found to have persistent mild to moderate hyperprolactinaemia. None of the three was impotent or taking any drug known to be associated with elevated serum prolactin, and anterior pituitary responses and pituitary fossa tomograms did not reveal any abnormality. The mean serum prolactin concentration of the 37 insulin-treated men was not significantly different from that of the 46 men on diet with or without anti-diabetic tablets, nor was there any significant difference between the mean serum prolactin concentrations of the 19 impotent men and of the 64 non-impotent men.
A Sensitive, Specific, Solid-Phase Enzymeimmunoassay for Plasma Progesterone
Authors: Joyce Brian G , Othick Ann H , Read Graham F , Riad-Fahmy Diana
Published: February 2014

A homologous enzymeimmunoassay (EIA) for plasma progesterone, using a horseradish peroxidase conjugate as enzyme label and an antiserum raised against a progesterone-11α-hemisuccinyl/BSA conjugate, is described. The antiserum was covalently linked to microcrystalline cellulose to facilitate separation of bound and free steroid; this solid-phase antiserum was stable for at least nine months when stored at 4°C. The freeze-dried enzyme label is also stable, having retained both enzymic and immunological activity for about four years. The EIA developed was specific and had the sensitivity (4·8 pg/tube) required for determining progesterone concentrations in plasma samples collected at any time during the menstrual cycle. EIA of plasma samples provided results which were in good agreement with a well validated radioimmunoassay (RIA). The specificity and inter- and intra-assay coefficients of variation in the EIA were strictly comparable with those of the RIA. The method described has been in use for two years and has been assessed in external quality assurance programmes established by the World Health Organization and the United Kingdom Department of Health and Social Security.
Sensitive Sandwich Enzyme Immunoassay for Serum Ferritin on Microtitre Plates
Authors: Linpisarn Sukanya , Kricka Larry J , Kennedy John H , Whitehead Thomas P
Published: February 2014

A solid-phase sandwich enzyme immunoassay for serum ferritin is described. The assay procedure was simple, showed good precision, and was suitable for the routine determination of serum ferritin concentration in a clinical laboratory. The assay compared well with a conventional radioimmunoassay for ferritin. The assay was extremely sensitive and had a detection limit of 2·2 pg.
Pre- and Post-Treatment Values of HDL Cholesterol and Total: HDL Cholesterol Ratio in Hyperlipoproteinaemic Subjects
Authors: Sale John K , Johnstone James H
Published: February 2014

High-density lipoprotein (HDL) cholesterol, total cholesterol, and triglyceride concentrations were measured in fasting blood samples from 74 controls and 185 patients with untreated primary hyperlipoproteinaemia. The mean HDL cholesterol levels and the total cholesterol: HDL cholesterol ratios were significantly different between male and female subjects. Only patients with Fredrickson type IV hyperlipoproteinaemia had HDL cholesterol concentrations significantly lower than the controls, but all subjects with hyperlipoproteinaemia had total: HDL cholesterol ratios significantly higher than control values.

Subsequent investigations were performed on 31 patients during treatment of the hyperlipoproteinaemia by diet alone or in combination with clofibrate. Responses were variable, but generally improvements in the concentrations of triglyceride and total cholesterol were accompanied by an unchanged or decreased total: HDL cholesterol ratio, although there was not necessarily an increase in the HDL cholesterol itself.
A Comparison of Free Thyroxine Concentration and the Free Thyroxine Index as Diagnostic Tests of Thyroid Function
Authors: Tuttlebee J W , Bird R
Published: February 2014

Serum free thyroxine concentrations, measured by the Immo Phase kit, and free thyroxine index values were compared in 200 subjects classified according to age, sex, and clinical diagnosis. The free thyroxine concentration was as good as the free thyroxine index in hyperthyroid, hypothyroid, elderly, and acutely ill patients and a better diagnostic index of thyroid status in pregnancy and in oral contraception.