bluuebunny/crossref_metadata_2025 huggingface dataset:
An Inexpensive, Rapid and Precise Affinity Chromatography Method for the Measurement of Glycosylated Haemoglobins
Authors: Hall Pauline M , Cook J G H , Gould B J
Published: February 2014

We have assessed an affinity chromatography technique, using commercially available materials, for the estimation of total glycosylated haemoglobin in the routine clinical chemistry laboratory. The method gives good discrimination between normals (7·31±0·92%) and diabetics (12·70±2·88%) and has excellent precision (CV 1·5-2·0%). Labile glycosylated haemoglobin is normally removed as it is so variable. There is no significant correlation between labile glycosylated haemoglobin and blood glucose. Immediate analysis of incubated haemolysates is preferable to storage of haemolysates or erythrocytes. The affinity gel can be reused about 16 times, but oxidation must be reduced by keeping the gel at 4°C in the dark when not in use. The cost of the gel is about 7p a test and 60 samples can be analysed in a working day. The method is not affected by the presence of up to 20% met-haemoglobin and should also give correct values for samples containing genetic variants of haemoglobin.
An Enzyme-Linked Immunoassay for the Measurement of Circulating Immune Complexes
Authors: Endo Yuichi , Yamamoto Ikuo , Ohtaki Sachiya , Yoshitake Shinji , Ishikawa Eiji
Published: February 2014

A solid-phase, enzyme-linked immunoassay for the quantitation of circulating immune complexes was developed using C1q. In this assay, the immune complexes in human serum are adhered to C1q-coated polystyrene tubes and then detected by a β-D-galactosidase-conjugated monovalent fragment (Fab′) of rabbit (anti-human IgG, γ chain-specific) IgG. The enzyme activity bound to the tubes was determined fluorometrically using 4-methylumbelliferyl-β-D-galactopyranoside as substrate. The sensitivity of this assay was as little as 100 ng/tube, which corresponded to 6 μg/ml when 16·7 μl of serum was assayed. The specificity of the assay was demonstrated by the following observations: (1) absence of cross-reaction of monomeric IgG; (2) non-detectability of immune complex in most of the sera from normal subjects; (3) parallelism of the standard curve with dilution of reference serum. The precision of the assay was proved by the demonstration of sufficient within-assay coefficients of variation (10·7–14·9%).
Determination of Blood Ammonia Using the Ammonia Checker
Authors: Huizenga J R , Gips C H
Published: February 2014

A new diffusion method employing bromocresol green for determination of blood ammonia (Ammonia CheckerR) using disposable reagent test-plates and a pocket-size colorimeter with direct readout of results was compared with an enzymatic method. The values obtained with the Ammonia Checker were slightly lower than those with the enzymatic method. Instead of arterial blood, capillary blood may be used for ammonia determination, but thorough cleansing of the fingertip used is necessary because of the high ammonia content of sweat.
Interfacing a Microcomputer to a Spectrophotometer for EMIT Assays
Authors: Morton John
Published: February 2014

Details of how to connect a microcomputer to a spectrophotometer are given. Four BASIC subroutines are described which allow the user to: sense sample input, transfer data to the microcomputer, purge the flowcell, and set a time delay loop. Initially designed for EMIT assays, the microcomputer could easily be adapted to other laboratory tests.
Direct Determination of Primidone in Serum or Plasma by a Magnetisable Solid-Phase Fluoroimmunoassay
Authors: Sidki A M , Rowell F J , Landon J
Published: February 2014

A solid-phase separation fluoroimmunoassay for primidone in plasma or serum was developed using antibodies coupled to magnetisable cellulose/iron oxide particles and a fluorescein-labelled primidone derivative as tracer. Endogenous fluorophores and other potentially interfering components in serum samples were reliably and completely removed at the time the antibody-bound and free fractions were being separated. The separation and wash steps were greatly facilitated by use of magnetic sedimentation. The assay reached equilibrium within 30 minutes; all normal reliability criteria were satisfied; and the results correlated closely with those of an established enzymoimmunoassay method. The assay is specific for primidone, and no detectable interference by all other commonly employed anticonvulsants was found at serum levels of 1 g/1.
Development of Radioimmunoassay for Gamma-Glutamyl Transferase Using Pancreatic Enzyme
Authors: Masuike Masanobu , Ogawa Michio , Kitahara Takeshi , Murata Atsuo , Matsuda Kazuhiko , Kosaki Goro
Published: February 2014

A radioimmunoassay (RIA) for the determination of gamma-glutamyl transferase (GGT) was developed using human pancreatic enzyme as antigen. The assay allows the determination of GGT in concentrations as low as 80 ng/ml, and it is reproducible and specific. A good parallel relation was demonstrated between the standard curve and dilution curves for serum, urine, bile, and partially purified kidney GGT. In normal individuals, the mean serum concentration of GGT determined by RIA was found to be 3·43 μg/ml (SD ± 1·20). Enzyme activity calculated from the GGT concentration measured by the radioimmunoassay using a regression equation was approximately twice as great as that determined by conventional enzyme assay.
Donnan Effect or Protein Interference in Ionised Calcium Measurements?
Authors: Thode Jørgen , Fogh-Andersen Niels , Siggaard-Andersen Mads , Siggaard-Andersen Ole
Published: February 2014

The observation that the ionised calcium concentration is higher if measured in the original serum sample than in an ultrafiltrate is examined by means of a theoretical model. It is concluded that this difference is a predictable consequence of the Donnan equilibrium and is not a result of protein interference with the calcium-specific electrode.
A Critical Evaluation of a New Fluorescence Immunoassay System for the Measurement of Serum Phenytoin Concentrations
Authors: Davis S J , Marks V
Published: February 2014

Results are presented which show that the Ames TDA™ phenytoin kit may be used with a shortened incubation time (5 minutes) and that, using a Fluorostat™ instrument, a single calibration curve can be stored and used effectively over a three-week period. The importance of temperature control when using a single calibration curve is emphasised. An unexplained finding was that higher results were obtained for phenytoin concentrations up to about 15 mg/1 with increasing incubation temperature. There was acceptable precision of measurement at all levels of phenytoin concentration, and there was no significant interference by haemoglobin, bilirubin, or lipids. The TDA results correlated well with those obtained using liquid chromatography ( y=0·39 + 0·98 x, r=0·98, where y=TDA and x=HPLC) and enzyme immunoassay ( y=0·08 + 0·93 x, r=0·96, where y=TDA and x=EIA).
Development of a Simple, Low-Cost, Continuous-Flow System for the Automated Radiommunoassay of Steroid Glucuronides
Authors: Barnard G J , Collins W P
Published: February 2014

A novel liquid-phase immunoassay is described which involves: competitive binding of the analyte and labelled antigen to specific antibodies; enzymic transformation of the free ligand to a more hydrophobic derivative; and separation of the antibody-bound and free ligand by partition of the reactants into an organic and aqueous phase. The principles of the method, described as ligand differentiation immunoassay, have been used in conjunction with a tritiated antigen to establish a continuous-flow system for the measurement of oestriol-16α-glucuronide in urine. Conventional autoanalyser (AAII) modules have been used, and the pump tubes and glass connections are standard accessories. The equipment is relatively inexpensive (£1500 + detector) and the reagents are readily available. Each sample takes 55 minutes to be processed, and 30 results are obtained per hour.
A Simple Automated Injection Technique for the High-Pressure Liquid Chromatographic Determination of Plasma Retinol
Authors: Howells D W , Brown I R F , Brooke O G , Newey V
Published: February 2014

We describe a rapid automated method for determination of retinol in 100 μl plasma. A lipid extract of plasma is analysed by reverse phase high pressure liquid chromatography using methanol-water as eluent. Automation of injection is achieved by adaptation of a Technicon AutoAnalyzer Sampler 2 coupled with a Micromedic dilution system and a pneumatically actuated loop injector. Twenty patients' specimens can be analysed in 4 hours, including extraction time, standards, and quality controls, with one extract injected every 4 minutes.
Comparison of Separation Methods in the 125I-Radioimmunoassay of Serum Cortisol
Authors: Gray Sadie M , Seth J , Beckett G J
Published: February 2014

Solid-phase first antibody (SP), liquid-phase double-antibody (DA), and preprecipitated double-antibody (PPT) separation methods have been compared in a radioimmunoassay (RIA) for cortisol in unextracted serum. Both double-antibody methods gave values for pools close to target values assigned by gas chromatography—mass spectrometry (GCMS) whereas the SP assay had a significant negative bias, p<0·001 (mean biases: SP —8%, DA —2%, PPT —3%). The SP and DA assays gave average values on patients' samples 12% and 4% lower than values by PPT. These differences could be attributed to different recoveries in the three methods. Between-assay precision of the DA and PPT systems was better than SP (mean CV: SP 11%, DA 7%, PPT 5%). This allowed sensitivity in the PPT assay comparable to that of SP and DA to be achieved, despite the less steep slope of the calibration curve. The DA and PPT assays have several practical advantages over SP. In addition, the PPT assay requires only a 1-hour incubation. It is concluded that the PPT separation system is the method of choice in terms of precision and practical convenience.
Effects of the Drug Disulphine Blue on Routine Biochemical Investigations
Authors: Halloran Stephen P , Torrens David J
Published: February 2014

Major interference by Disulphine Blue in the colorimetric determination of amylase, albumin, protein, iron and total iron-binding capacity is described. The drug, an intense blue dye, was administered intravenously to a patient before surgery to allow demarcation of devitalised bone. Successive sampling showed the drug to have a half-life of 30 hours, to remain visible for 150 hours in both urine and blood, and to cause significant interference with the five analytes for up to 2 1/2 days. The 640 nm absorbance peak of Disulphine Blue was shown to be pH-dependent, and therefore the reaction conditions of individual methods may influence the degree of interference.
Salivary Cortisol: A Better Measure of Adrenal Cortical Function than Serum Cortisol
Authors: Vining Ross F , McGinley Robynne A , Maksvytis Joseph J , Ho Kian Y
Published: February 2014

Salivary Cortisol concentration was found to be directly proportional to the serum unbound Cortisol concentration both in normal men and women and in women with elevated cortisol-binding globulin (CBG). The correlation was excellent in dynamic tests of adrenal function (dexamethasone suppression, ACTH stimulation), in normals and patients with adrenal insufficiency, in tests of circadian variation and randomly collected samples. Women in the third trimester of normal pregnancy exhibited elevated salivary Cortisol throughout the day. The relationship between salivary and serum total Cortisol concentration was markedly non-linear with a more rapid increase in salivary concentration once the serum CBG was saturated. The rate of equilibrium of Cortisol between blood and saliva was very fast, being much less than 5 minutes. These data, combined with a simple, stress-free, non-invasive collection procedure, lead us to suggest that salivary Cortisol is a more appropriate measure for the clinical assessment of adrenocortical function than is serum Cortisol.
Haematological and Biochemical Parameters in an Industrial Workforce
Authors: Gidlow David A , Church John F , Clayton Barbara E
Published: February 2014

Biochemical and haematological data for two consecutive years are presented on about 2000 people from the workforce of a large chemical company. The data are examined for the influence of sex, age, season, time of blood sampling, and patterns of work on the various indices.

In addition to the results confirming previously published work relating to the effects of age and sex, they provide interesting new information on the possible influences of seasons and patterns of work, that is, whether the subjects were shift or day workers. Further studies on the influence of these various factors are required, and our on-going survey will perhaps provide more definite data in due course. The findings show the importance of quantifying these variables, particularly in an industrial workforce where minor changes may be of significance.
Stability of Four Steroids in Lyophilised Human Serum
Authors: Das Rose E Gaines , Calam D H , Mitchell F L , Woodford F P , Cawood Marion , Gaskell S J , Joyce B , McMillan Mary , Wheeler M J
Published: February 2014

The stability of a preparation of lyophilised serum and its suitability for use as a reference material for routine assays of Cortisol, oestradiol, and progesterone have been studied in four laboratories with a variety of assay systems. Cortisol and oestradiol were also measured by gas chromatography-mass spectrometry. The lyophilised serum was suitable for use in all routine and reference assay methods examined, with between-method variability no greater than that for frozen serum pools. The concentrations of Cortisol, oestradiol, and progesterone were predicted by accelerated degradation studies to decline by 0·01% per annum if the preparations were to be stored at —20°C. The testosterone content of the preparation, determined in one laboratory, provided no evidence for degradation. The preparation can be shipped for use at ambient temperature without deleterious effect.
Thyroxine and Thyroxine-Binding Globulin: Discriminant Formulae for the Separation of the Diagnostic Classes of Thyroid Function
Authors: Noe Dennis A
Published: February 2014

The biochemical classification of thyroid functional status is often accomplished by the use of the thyroxine to thyroxine-binding globulin (T4:TBG) ratio. It has recently been shown, however, that the reference range of the T4:TBG ratio varies with the concentration of TBG. This makes the T4:TBG ratio an unwieldy diagnostic index. A more accurate and economical way to define thyroid function using T4 and TBG measurements is by linear discriminant formulae. This is so because T4 varies linearly with TBG at the T4 reference limits over a wide range of TBG concentrations. Using the T4 reference ranges established by Attwood and Atkin ( Ann Clin Biochem 1982; 19: 101–3), the following formulae are obtained:

T4 (nmol/l)—4·05 TBG (mg/l)>94·5 indicates hyperthyroidism; T4 (nmol/l)—2·72 TBG (mg/l)<23·8 identifies hypothyroidism.
The Routine Investigation of Urinary Organic Acids in Selected Paediatric Patients: Results over a 2 1/2-Year Period
Authors: Bennett M J , Green Anne , Pollitt R J , Worthy E
Published: February 2014

Over a 2 1/2-year period 13 patients with inborn errors of organic acid metabolism, excluding undifferentiated lactic acidosis, have been diagnosed in our laboratories. The diagnostic yield in patients who had not previously been investigated by organic acid chromatography was 1 in 25, the majority of cases having presented with metabolic acidosis. A larger number of non-specific abnormalities were also detected. This type of investigation is beset with pitfalls and is extremely labour intensive.
The Implications of Assaying External Quality Control Sera under ‘Special Conditions’
Authors: Rowan R M , Laker M F , Alberti K G M M
Published: February 2014

Two identical series of Wellcome quality control specimens were analysed by different procedures. One series was entered into the laboratory in the same way as patients' specimens while the other was analysed under special favourable conditions. This involved assaying the samples in replicate in different batches, omitting transcription errors and outliers, and placing the sample in a position following a calibration standard or an internal control. It was found that a significantly higher position in overall league ranking was achieved by assaying the control under ‘special conditions’.
Gas Chromatographic Screening for Drugs and Metabolites in Plasma and Urine
Authors: Jarvie D R , Simpson D
Published: February 2014

There is an increasing need for sensitive and specific methods for toxicological screening. Development of a dual-column gas chromatography system for the screening of drugs and metabolities in the plasma of poisoned patients is described. The system has been evaluated using plasma from a well-documented series of patients presenting with overdose, and results obtained have been compared with results of specific assays for the groups of drugs encountered. The method has been found to be of value in the treatment of poisoned patients despite its apparent insensitivity to certain more polar drug metabolities such as nortriptyline and desmethyldiazepam.
Problems in the Determination of Erythrocyte Protoporphyrin by Ethyl Acetate-Acetic Acid Extraction
Authors: Doran Donna , Mitchell Douglas G
Published: February 2014

Three problems with the ethyl acetate-acetic acid method of protoporphyrin analysis were identified: (1) protoporphyrin extraction from whole blood may yield low recoveries in comparison with extraction from prediluted blood; (2) recovery of protoporphyrin is low with some batches of ethyl acetate, but such unsatisfactory reagent can be identified by an iodide oxidation test; (3) protoporphyrin standards prepared with deionised water may be unstable. However, glass-distilled water is satisfactory.
Interference by Thimerosal in Cholesterol Estimation by the CHOD-PAP Method
Authors: Briggs Catherine J , Anderson Deborah , Muirhead R A
Published: February 2014

We report that interference with the cholesterol assay using the cholesterol oxidase: p-aminophenazone method which is observed during lipoprotein preparation, is caused by the anti-bacterial agent thimerosol used in the preparation. We suggest that an alternative anti-bacterial agent should be used in these circumstances.
The Effect of Instrument Variables on Calculation Factors for Standardisation of Colorimetric Analyses
Authors: Peake M J , Pejakovic Maria , Fraser C G
Published: February 2014

A number of colorimetric methods, particularly enzyme activity assays, are usually standardised using calculation factors based on the molar absorptivity of a principle reactant or product. Such methods are subject to long-term variation. The relationship between long-term variation in results and instrument variables affecting calculation factors has not been quantitated. In this study, we have shown that, on a centrifugal analyser having a within-run coefficient of variation of less than 1%, instrument variables affecting calculation factor alone could result in changes in results of up to 8·5% over 75 days. We therefore advocate daily use of a solution of potassium dichromate to monitor instrument variables that can independently affect calculation factors and within-run imprecision. This procedure is useful for maintaining long-term performance and for differentiating problems of instrumental or chemical origin.
Quality Assurance in the Third World—the Singapore Experience
Authors: Tan It-Koon , Jacob Edward
Published: February 2014

This paper reviews the current status of quality assurance in clinical biochemistry laboratories in Third World countries, particularly the developments in Singapore which in some respects are very similar to those of other developing countries. Some of the common problems are highlighted and recommendations for improvement proposed.
Plasma Emission Spectrometry: Measurement of Calcium, Phosphorus and Chromium in Metabolic Balance Studies
Authors: Roberts N B , Fairclough D , Taylor W H
Published: February 2014

Direct-current plasma emission spectrometry determines food calcium and phosphorus, faecal calcium and chromium, and urinary calcium and phosphorus accurately, precisely and rapidly without acid digestion or dry ashing. Food and faeces are homogenised, diluted and aspirated directly into the plasma. The method makes metabolic balances swifter and less labour-intensive; it enables the use of chromium sesquioxide as an inert marker, for perchlorate digestion is avoided. Both plasma emission (–9.9%) and a dry ashing procedure (–13.5%) give lower values for food phosphorus than those derived from food tables.
The Relationship between Liver Function Tests and Alcohol Intake in Patients Admitted to an Alcoholism Unit
Authors: Evans J R , Ogston S , Guthrie Anne , Johnston B , McKechnie L
Published: February 2014

Values of various blood plasma tests have been determined in heavy drinkers admitted to an Alcoholism Unit and in a reference group of occasional social drinkers. These tests were total protein, albumin, bilirubin, alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), asparate amino transferase (AST) and amylase.

The aim of this study was to assess the reliability and validity of GGT and AST as indices of alcohol intake in heavy drinkers entering an Alcoholism Unit. The data indicate that in the patients group intra-personal variance and analytical variances are relatively small compared with the between-person variance. The data also indicate, however, that in the patients group GGT and AST are not valid group indices of alcohol intake since the between-person variation is large and the correlation with alcohol intake is weak due to large differences in the dose-response relationship between individuals. AST and GGT are poor indicators of alcohol intake in admissions to an Alcoholism Unit.
Thyroid Hormone Concentrations and Free Thyroxine Status in Neonatal Venous and Capillary Serum Pairs
Authors: O'Grady Collen M , Franklin R C
Published: February 2014

The levels of thyroid hormones in paired venous and capillary serum samples taken from 68 healthy full-term neonates were determined by radioimmunoassay. Compared with capillary values, total thyroxine (T4), thyrotropin (TSH) and thyroxine-binding globulin (TBG) each showed a significant decrease in venous serum. The mean venous and capillary concentrations of tri-iodothyronine (T3), reverse tri-iodothyronine (rT3) and free thyroxine (fT4) were not significantly different; however, in each case the fitted linear relationship suggested that venous and capillary values were not concordant ( P<0·02, P<0·01, P<0·05 respectively). Both the T3 uptake test and the free thyroxine index (FTI) were significantly higher in venous serum, while the ratios of T4 to TBG in paired samples were equivalent. These results suggest that consistent sample collection and assay methods should be applied when assessing neonatal thyroid status, particularly if comparison of results is intended.
Evaluation of β-D-Galactosidase from Escherichia Coli and Horseradish Peroxidase as Labels by Sandwich Enzyme Immunoassay Technique
Authors: Imagawa Masayoshi , Hashida Seiichi , Ohta Yohsuke , Ishikawa Eiji
Published: February 2014

β-d-galactosidase from Escherichia coli and horseradish peroxidase were evaluated as labels of Fab' in dose-response curves for human α-fetoprotein and human chorionic gonadotropin by sandwich enzyme immunoassay technique using fluorogenic substrates for enzyme assay. The non-specific binding of Fab'–peroxidase conjugates to IgG-coated polystyrene balls was less than that of Fab'-β-d-galactosidase conjugates, and the affinity-purified Fab'–peroxidase conjugates gave more sensitive dose-response curves for these antigens than the corresponding β-d-galactosidase conjugates. However, a large quantity of Fab'–peroxidase conjugates was required and a longer incubation was necessary for the peroxidase assay, since the peroxidase assay was much less sensitive than the β-d-galactosidase assay. Other advantages and disadvantages of the two enzymes are discussed.
Classification of Hyperlipoproteinaemias by Computer Interpretation
Authors: Loughlin Jane F , Leung F Y , Henderson A R
Published: February 2014

We have developed a microcomputer-based system for the classification and interpretative reporting of lipoprotein electrophoretic data. The decision logic takes into consideration the sex and age of the subject, the concentration of total cholesterol and triglyceride, the appearance of the serum after standing at 4°C for 18 h or more and the type of lipoprotein abnormality observed from polyacrylamide disc gel electrophoresis to produce a phenotype according to the classification developed by Fredrickson and co-workers. As the hyperlipoproteinaemia may be primary or secondary to a number of associated conditions, these are included in the report with the six possible phenotypes. A high correlation (98·7%) between manual and computer interpretation was found for 152 consecutive cases of lipoprotein phenotyping.
A Critical Assessment of Plasma Alkaline Ribonuclease as an Indicator of Protein Nutritional Status in Infancy
Authors: Scott P H , Berger H M , Wharton B A
Published: February 2014

Plasma alkaline ribonuclease (RNase) was measured at birth and during infancy to assess its usefulness as an indicator of protein nutritional status. Cord blood enzyme activity did not indicate intra-uterine protein malnutrition in the less well-grown babies. Differences in enzyme activity were found which related to the quality of the dietary protein fed to both preterm and term light for gestational age babies. Higher activity on day 7 in those infants fed a predominantly curd protein formula suggested that this was less well utilised than a curd and whey protein formula. Serial enzyme measurements in four infants with metabolic disease showed how the enzyme activity altered in response to changes in the quantity of dietary protein. These results are critically discussed.
Effects of Storage and Repeated Freezing and Thawing on Plasma Cholinesterase Activity
Authors: Turner J M , Hall R A , Whittaker M , Kricka L J
Published: February 2014

Plasma cholinesterase activity, determined using either benzoyl choline or butyrylthiocholine as substrate, is stable for prolonged periods (> 12 months) when stored at −20°C. Likewise, repeated freezing and thawing of plasma did not markedly affect cholinesterase activity.
Simplified Analytical Methods for the Measurement of the Synthesis Rate of Plasma Proteins in Vivo by the [14C]Carbonate Method
Authors: Caine S , Fleck A
Published: February 2014

We describe a method for obtaining the specific activity of 14C in urea, essential in the measurement of the synthesis rate of a plasma protein in vivo, which is simpler than the original procedure. The principle is the measurement of 14CO2 and NH4+ separately, after incubation with urease. A simple alteration gives samples of 13CO2 for mass spectrometry. The ‘recoveries’ of 14C and 13C in urea were invariably between 90 and 96% and the CV was 3%.
A Single-Step Immunoradiometric Assay for the Measurement of Serum Ferritin
Authors: Perera Praemi , Worwood Mark
Published: February 2014

An immunoradiometric assay (IRMA) which can be carried out in a single working day is described here. The assay is comparable to the conventional IRMA with respect to both sensitivity and reproducibility and is less labour intensive.
Performance of Three Enzymic Methods for Filter Paper Glucose Determination
Authors: Burrin J M , Price C P
Published: February 2014

Collection of blood spots on filter paper offers a practical alternative for home monitoring of diabetic patients. We have compared the merits of three protein precipitants, trichloracetic acid (TCA), perchloric acid (PCA) and sulphosalicylic acid (SSA) for the elution of glucose from the filter paper, and their subsequent effects on three enzymic methods, glucose dehydrogenase (GDH), hexokinase (HK), and glucose oxidase (GOD) for the determination of glucose using a microcentrifugal analyser. The combination of TCA elutant with the GDH method was superior with respect to time course of reaction and elution time from the filter paper, and was chosen for routine use. Within- and between-batch precision for this method was 2·7% and 3·2% respectively at normal glucose concentrations. Recovery of glucose added to whole blood was 110 ± 5%. Comparison with an automated glucose oxidase method for plasma glucose gave a slope of 1·1, intercept of −0·7 and a correlation coefficient of 0·9 ( n = 64).

We conclude that the combination of TCA and glucose dehydrogenase provides a robust, precise and accurate method for the quantitation of glucose in filter-paper blood spots. The procedure offers increased sensitivity and better precision than GOD methods. The use of TCA as elutant gives a faster elution time and has the least effect on any of the enzymic methods.
A Rapid Assay for 17αOH-Progesterone in Plasma, Saliva and Amniotic Fluid Using a Magnetisable Solid-Phase Antiserum
Authors: Dyas J , Read G F , Guha-Maulik Tapati , Hughes I A , Riad-Fahmy Diana
Published: February 2014

A radioimmunoassay suitable for measurement of 17αOH-progesterone concentrations in small aliquots of plasma (20 μL), amniotic fluid (20 μL) and saliva (200 μL) is described. The assay features an antiserum raised against a 17αOH-progesterone-3-(O-carboxymethyl)oxime/BSA conjugate coupled to a magnetisable, solid-phase support; the homologous radioligand is a 125I-iodohistamine conjugate. This combination of a γ-emitting ligand and a magnetic-separation procedure has the advantage of reducing assay time and cost; it also allows processing of plasma and saliva samples in the same assay batch. The method has satisfactory sensitivity, precision and accuracy. Data derived from clinical studies of patients with congenital adrenal hyperplasia indicate the usefulness of this assay in routine practice.
A Simple Paired-Ion Liquid Chromatography Assay for Serotonin in Cerebrospinal Fluid, Platelet-Rich Plasma, Serum and Urine
Authors: Kwarts E , Kwarts J , Rutgers H
Published: February 2014

Anderson and co-workers1 recently described a simple high-performance liquid chromatographic/fluorimetric assay for serotonin and tryptophan, in which deproteinised samples were directly injected. Using this method routinely, we frequently observed interference which could not sufficiently be resolved from serotonin to allow accurate quantitation. However, when the amine was isolated by ion-exchange chromatography prior to HPLC separation as advocated by Koch and Kissinger,2 chromatograms were obtained with practically no extraneous peaks. In this paper the application of this method for the determination of serotonin in CSF, plasma, serum and urine is described.
Colorimetric Measurement of Glycosylated Protein in Whole Blood, Red Blood Cells, Plasma and Dried Blood
Authors: Eross J , Kreutzmann D , Jimenez M , Keen R , Rogers S , Cowell C , Vines R , Silink M
Published: February 2014

A colorimetric method for the measurement of whole-blood glycosylation (WBG), glycosylated haemoglobin in red blood cells (GHb), glycosylated plasma protein (GPP) and dried-blood glycosylation (DBG) is described which is rapid, inexpensive and precise. GHb correlated well with HbA1 measured by cation-exchange chromatography and was also correlated with WBG, DBG and GPP. DBG, which showed good correlation with GHb, could be measured on several drops of blood dried on filter paper treated with glucose oxidase. Filter papers are posted to the laboratory prior to clinic visits, and by having the DBG result available more rational diabetic management is possible. For DBG, the intra- and inter-assay coefficient of variation at three levels is less than 6%. Reference values in non-diabetic children have been calculated and are compared with values obtained in ‘good’ clinical diabetic control and in ‘fair’ control. The filter-paper assay DBG method has a high degree of patient acceptance.
Determination of Retinol-Binding Protein in Serum by Kinetic Immunonephelometry with Polyethylene Glycol Pretreatment
Authors: Hallworth M J , Calvin Jacqueline , Price C P
Published: February 2014

This work describes the use of polyethylene glycol as a pretreatment reagent to remove endogenous light scattering material from serum samples prior to automated immunonephelometric analysis on a centrifugal analyser. An assay system for retinol-binding protein is described, which allows rapid (10 minutes) quantitation of retinol-binding protein in serum samples with a detection limit of 5 mg/L and between-assay coefficients of variation ranging from 2·9% to 4·0%. The assay range is 5–80 mg/L and accuracy comparisons with a Mancini single radial immunodiffusion method yield a regression line y=0·89x+0·52 ( r=0·98, n=22). The problem of analyte precipitation associated with use of pretreatment regimes is discussed.
Plasma Levels of Vitamin C Components in Normal and Diabetic Subjects
Authors: Newill Alison , Habibzadeh N , Bishop N , Schorah C J
Published: February 2014

Recent reports of high dehydroascorbic acid levels in Asian subjects suffering from diabetes mellitus have led us to examine plasma dehydroascorbic acid levels in diabetic and non-diabetic Europeans. We can find no evidence that diabetic patients have higher plasma dehydroascorbic acid levels than nondiabetics, and consider some possible reasons for the discrepancy between this finding and those of earlier reports.
External Quality Assessment of Quantitative Urinary Analysis
Authors: Legg E F , Hurrell A E
Published: February 2014

An external quality-assessment scheme was initiated among a group of 13 clinical chemistry laboratories for the urinary analysis of calcium, chloride, creatinine, glucose, osmolality, phosphate, potassium, protein, sodium, urate and urea and also for the estimation of creatinine clearance.

The greatest inter-laboratory imprecision occurred in the assay of urinary protein. The results of the survey are compared with similar schemes elsewhere and their significance discussed.
The Evaluation of Imprecision in Collaborative Immunoassay Quality-Assessment Programmes
Authors: Compton P , Cole Benedicte , Stuart Margaret , Egan G
Published: February 2014

The calculation of within-laboratory imprecision in quality-assessment (QA) programmes normally involves combining data from different analyte concentrations to calculate an average standard deviation (SD) or coefficient of variation. However, for immunoassay neither of these parameters is concentration independent.

This paper describes a method of calculating within-laboratory imprecision in QA programmes by assuming a linear relationship between SD and analyte concentration. This method is used in programmes conducted by the Australian Joint Working Party for Quality Control in Immunoassay to calculate imprecision at the limits of the reference range. Results from these programmes show that this method better represents the differences in imprecision between analytes, methods and laboratories than the calculation of a single imprecision parameter. The method is trivial for a computer and its robustness has been validated by Monte Carlo simulation. It is suggested that major differences in laboratory performance between different QA programmes may be due to inappropriate calculation of single imprecision parameters.
Evaluation of the Enzymatic Assay of Serum Uric Acid with 2,2′-Azino-Di(3-Ethylbenzthiazoline-6-Sulphonate) (ABTS) as Chromogen
Authors: Majkić-Singh Nada , Said Bouz Asal , Spasić Slavica , Berkeš Ivan
Published: February 2014

A spectrophotometric method for the determination of serum uric acid based on the oxidation of 2,2′-azino-di(3-ethylbenzthiazoline-6-sulphonate) by use of uricase and peroxidase has already been reported. The method is very precise (CV <4·7%). The standard curve is linear up to 4640 μmol/L. Comparison with other enzymatic methods gave good correlation. The method gave results 9% lower than the phosphotungstate method. The effects of bilirubin, haemoglobin, glucose, ascorbic acid, anticoagulants and purine compounds were studied. The reference values for this method are 140·8–407·8 μmol/L for female subjects and 145·6–514·7 μmol/L for male subjects.
Biochemical and Haematological Response to Alcohol Intake
Authors: Shaper A G , Pocock S J , Ashby D , Walker M , Whitehead T P
Published: February 2014

In a clinical survey of 7735 middle-aged men, alcohol consumption has been related to 25 biochemical and haematological measurements obtained from a single blood sample. Most measurements showed some association with alcohol consumption, gamma-glutamyl transferase (GGT) being the most strongly associated. Lead, mean corpuscular haemoglobin (MCH), mean corpuscular volume, high-density lipoprotein-cholesterol (HDL-C), urate and aspartate transaminase also showed substantial associations with alcohol intake.

Using a discriminant analysis technique, a simple score based on five variables (GGT, HDL-C, urate, MCH and lead) provided the best discrimination between heavy drinkers (e.g. more than three pints of beer daily) and occasional drinkers, but still failed to identify more than half of the heavy drinkers. This combined score may prove a useful measure of an individual's biochemical/haematological response to alcohol consumption for use in epidemiological and clinical studies of alcohol-related disorders. The use of such indices should complement but not replace measures of alcohol intake derived from questionnaires.
Glucose Tolerance Test and Glycosylated Haemoglobin Measurement for Diagnosis of Diabetes Mellitus—An Assessment of the Criteria of the WHO Expert Committee on Diabetes Mellitus 1980
Authors: Albutt Eileen C , Nattrass M , Northam B E
Published: February 2014

Fasting glycosylated haemoglobin was analysed in 535 consecutive patients having an oral 75 g glucose tolerance test for diagnostic purposes. A reference range for fasting glycosylated haemoglobin was established from patients with a non-diabetic glucose tolerance test as defined by the World Health Organisation Expert Committee on Diabetes Mellitus. The predictive value of a glycosylated haemoglobin of over 100% (mean normal + 3 SD) for detecting a diabetic glucose tolerance test was 89% but sensitivity was only 43%.

A raised glycosylated haemoglobin is useful for confirming the diagnosis of diabetes mellitus in patients with long-standing hyperglycaemia but glycosylated haemoglobin is within the reference range in many patients with newly developed diabetes or other minor abnormalities of glucose tolerance. The glucose tolerance test must remain the test of choice in these patients.
Lack of Comparability between CEA Analyses Using Three Different Methods
Authors: Davidson Helen , Pledger D R , Belfield A
Published: February 2014

Three different methods for the assay of carcinoembryonic antigen were investigated—radioimmunoassay, enzyme-linked immunoassay, and a commercial immunoradiometric assay. Two standard preparations of CEA were used: the 1st British Standard (73/601) and a commercial preparation obtained as a component of the IRMA kit.

Serum samples were assayed by each method against each standard material. Significant differences between results were obtained when the different methods were compared. When using the two standards in the same assay system no significant differences were found between results. A possible explanation and the implications of these findings for the routine assay of CEA are discussed.
A Method for the Measurement of a Diene-Conjugated Derivative of Linoleic Acid, 18:2(9,11), in Serum Phospholipid, and Possible Origins
Authors: Iversen S A , Cawood P , Dormandy T L
Published: February 2014

A method is described for the measurement of a diene-conjugated derivative of linoleic acid, 18:2(9,11), in the phospholipid fraction of serum. The method is based on enzymatic hydrolysis, solid-phase sample preparation, and high-performance liquid chromatography (HPLC). Phospholipid esterified 18:2(9,11) can be detected in serum from normal individuals, and a provisional normal range is provided. The possible origins of 18:2(9,11) and the potential application of this method to the measurement of free radical damage to linoleic acid in vivo is discussed.
Patient-Orientated Metered Capillary Blood Collection
Authors: Holman R R , Rees S G , Moore J C , Bown E G , Turner R C
Published: February 2014

A small collector bottle, with a precision-moulded top, allows capillary blood from a finger-prick to be automatically metered into a diluent for subsequent laboratory analysis. This device, which has been successfully used by patients to obtain full blood counts, glycosylated haemoglobin values and blood glucose measurements, may have wide application.
The Diagnostic Value of Glycated Haemoglobin Levels in Post-Mortem Blood
Authors: Hindle Eric J , Rostron Glenise M , Gatt John A
Published: February 2014

Glycated haemoglobin (HbA1) in post mortem blood was estimated following electrophoretic separation. HbA1 was measured in preserved and unpreserved specimens and its stability in vitro was studied. No significant change in the proportion of HbA1 was observed in samples stored for more than 40 days at 4°C.

Specimens were analysed for glucose and HbA1. There was poor correlation between these parameters, and no significant difference between the mean values of HbA1 in specimens collected within 24, 48 and 72 or more hours following death, from subjects with no previous history of diabetes. The levels were within the laboratory reference range, whilst eight specimens collected from diabetic subjects demonstrated elevated levels. There was no significant difference in HbA1 levels collected from different sites in the body even though the glucose levels showed some variation.

The measurement and apparent stability of HbA1 post mortem may be a more useful diagnostic test than glucose alone where diabetes may be suspected.
The Development of a Fluoroimmunoassay for β-2-Microglobulin in Serum
Authors: Playford R J , Dawnay Anne , Cattell W R , Landon J
Published: February 2014

A liquid-phase fluoroimmunoassay has been developed for the measurement of β-2-microglobulin in undiluted serum or plasma. Protein labelled with fluorescein-isothiocyanate at a molar ratio of 1:2 respectively is employed as a tracer together with an antiserum to β-2-microglobulin raised in a sheep. Separation is achieved by means of rabbit anti-sheep immunoglobulin G and, following precipitation of the bound fraction by centrifugation, the free fraction together with any potentially interfering factors is removed in the supernatant. Finally the precipitate is dissolved and the fluorescence measured.

The assay is simple and rapid in that all reactants, including the second antibody, can be added at the start of the assay and equilibrium is attained within 60 min. The assay is reproducible and sufficiently sensitive to allow measurement of normal serum levels and has a wide range avoiding the need for sample dilution. Results correlated well with those of an established radioimmunoassay.
A Study of Sweat Sodium and Chloride; Criteria for the Diagnosis of Cystic Fibrosis
Authors: Green Anne , Dodds Patricia , Pennock Charles
Published: February 2014

Retrospective analysis of sodium and chloride results from sweat tests carried out in Bristol and Sheffield has shown that misdiagnosis of cystic fibrosis (false negatives and false positives) is considerably less if sodium and chloride are both measured. In patients with cystic fibrosis the chloride concentration is usually higher than the sodium, whereas in normal subjects the reverse usually occurs. This observation is particularly useful when borderline results (50–70 mmol/L) are obtained.
A Steady-State Gel Filtration Method on Micro-Columns for the Measurement of Percentage Free Testosterone in Serum
Authors: Wheeler M J , Nanjee M N
Published: February 2014

A method is described for measuring the percentage of free testosterone in serum using steady-state gel filtration on micro-columns of Sephadex G50 (fine). The method has a coefficient of variation of 4·0% and up to 20 samples can be processed in a day.

Reference ranges have been established for normal women at different stages of their menstrual cycles and for normal men; there is good agreement with values published by workers using other methods. This method combined with a specific and precise method for measuring total testosterone opens up the possibility for the routine measurement of free testosterone concentration in serum.
A Simple, Rapid and Cheap Radioimmunoassay for Plasma Digoxin
Authors: Moore R A , Turner Marilyn , Cousins Janet , Gales Mary
Published: February 2014

A radioimmoassay for digoxin is described which uses commercially available reagents. Two assay procedures are used, one for batch assays, and another, which needs a 5 minute incubation only, for ‘stat’ assays. The methods are shown to be simple, rapid, precise and inexpensive and the batch procedure compared well with the Amerlex digoxin method for 63 patient samples.
Methodological Considerations in the Determination of Plasma Catecholamines by High-Performance Liquid Chromatography with Electrochemical Detection
Authors: Bouloux Pierre , Perrett David , Besser G M
Published: February 2014

We report on a systematic investigation into some frequently encountered problems in the estimation of catecholamines in plasma and biological fluids using high-performance liquid chromatography with electrochemical detection. The kinetics of adsorption and desorption of catecholamines from plasma on to alumina has been studied using laboratory-prepared and some commercial aluminas with various acids. Chromatographic conditions yielding optimal resolution and sensitivity have been characterised. Some possible interfering peaks have been identified. The stability of catecholamines in plasma has been studied.
Experience with a Haemagglutination Inhibition Test for Morphine Detection in Urine
Authors: Rambohul E , Ruprah M
Published: February 2014

A commercially available haemagglutination inhibition (HI) test (Drug Test Opiates, Boehringer Biochemia Robin) for the detection of morphine in urine has been evaluated alongside a routine TLC method and a radioimmunoassay. TLC gave positive results for morphine, codeine or dihydrocodeine in 138 out of 300 samples from patients attending a drug dependence treatment unit. These were also positive according to the HI test, but a further 76 of the TLC negative samples also gave positive results with this technique. The TLC negative samples (162) were also analysed by RIA and positive results were obtained for 96 samples. Neither of the immunological tests could distinguish between morphine, codeine or dihydrocodeine, but no reactions with other abused drugs were observed.
The Calibration of Total Serum Bilirubin Assays
Authors: Turnell D C
Published: February 2014

Bilirubin assays yield variable results due to the lack of a universal calibrant. The preparation of a bilirubin calibrant is associated with the following problems: (a) only unconjugated bilirubin is available in a ‘pure’ form and this is of doubtful stability, (b) the test for its purity is arbitrary, (c) the true molar absorptivity of bilirubin is unknown, (d) due to the various specificities of methods, the calibrant has to be in a protein matrix, (e) the matrix alters the properties of bilirubin and (f) there is no definitive bilirubin assay. The use of a lyophilised human-based bilirubin calibrant should permit accurate standardisation of the method of Jendrassik and Grof and that of Hertz.