bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the Accuracy of a Quantitative Kit Radioimmunoassay for Free Thyroxine
Authors: Symons R G , Wilke T J , Wellby M L
Published: February 2014

Experiments designed to determine the accuracy of the Corning Immophase Free T4 assay revealed that there was a marked perturbation of thyroxine binding to the serum proteins during the assay; binding of 125I-T4 to the immobilised T4 antibody in the absence of merthiolate increased considerably with buffer dilution of serum; and the free thyroxine concentration declined significantly during pregnancy. These changes in measured fT4 were not observed with an equilibrium dialysis-radioimmunoassay procedure. The assay was precise, easily performed, and as effective as the free thyroxine index (FTI) in diagnosing thyroid disease. We conclude that the assay does not provide an accurate quantitative estimation of serum fT4 concentration in samples with elevated TBG concentration and that the kinetic principles on which the assay is based are altered as serum binding-protein concentration is reduced (serum dilution). Both FTI and fT4 (Corning) data in pregnant patients should be interpreted with caution and with reference to clinical symptomatology and other thyroid function tests.
Serum Free Thyroxine Concentrations in Subjects with High Circulating Levels of Thyroxine-Binding Globulin
Authors: Ashwell K , Hopton M R , Harrop J S
Published: February 2014

Serum free thyroxine (FT4) and thyroid hormone-binding protein concentrations were measured in pregnant women, stilboestrol-treated patients, and subjects with congenital thyroxine-binding-globulin (TBG) excess. In pregnant and stilboestrol-treated patients matched for TBG concentrations, serum FT4 concentrations measured by the Amerlex technique and by calculation, were reduced, as also was the total thyroxine (TT4)/TBG ratio. In congenital TBG excess Amerlex and calculated FT4 concentrations were normal whereas the TT4/TBG ratio was low. In contrast to the Amerlex method, FT4 concentrations by the Immophase procedure were normal in pregnant and stilboestrol-treated individuals and high in congenital TBG excess.

We conclude that (i) reduced FT4 concentrations in pregnancy are related to an oestrogen effect rather than to some other pregnancy-associated factor, (ii) the TT4/TBG ratio gives a misleading indication of FT4 concentration in congenital TBG excess, and (iii) that when TBG concentrations are raised Immophase gives higher FT4 values than Amerlex or calculation when each is compared to FT4 values in their normal respective control group.
An Improved Gas Chromatographic Determination of Urinary Catecholamine Metabolites
Authors: Taylor Garry F , Duong Thach , Carter Norris G
Published: February 2014

We describe an improved gas chromatographic method for the determination of 3-methoxy-4-hydroxymandelic acid (vanilmandelic acid), 3-methoxy-4-hydroxyphenyacetic-acid (homovanillic acid), and 3-methoxy-4-hydroxyphenylethylene glycol. By incorporating slight modifications to established procedures, this method allows the urinary metabolites to be measured more rapidly and with better resolution. The procedure uses an internal standard and involves ethyl acetate extraction, silylation, and chromatography using a combination of two different stationary phases. The technique is simple and reliable and may be easily incorporated as a routine laboratory procedure.
A Sensitive Method for the Measurement of Glycosylated Plasma Proteins Using Affinity Chromatography
Authors: Gould Barry J , Hall Pauline M , Cook John G H
Published: February 2014

We describe a simple, sensitive affinity technique for the routine measurement of glycosylated plasma proteins in clinical laboratories. The commercially available phenylboronic acid gel used for the chromatography has recently been marketed as a kit for this purpose (Glycogel Test Kit, Pierce Chemical Co). The manufacturers of this kit recommend loading 200 μl neat plasma to each 1 ml gel column. This high loading is to enable the direct measurement of protein in the bound and unbound fractions at 280 nm. This loading is consistent with 10–15 mg protein being added per ml gel. Our results show that protein levels greater than 2 mg per ml gel overload the column. Therefore we used a modification of the more sensitive Bradford procedure to measure protein. The method discriminates between normals (6·29 ± 1·87%) and diabetic patients (12·62 ± 3·36%) and has good precision (CV 4–6%). The results obtained correlate with the colorimetric method using thiobarbituric acid ( r = 0·70) and with glycosylated haemoglobin ( r = 0·82).
A Basic Program for Serum Cholinesterase Phenotyping Using a Microcomputer
Authors: Loughlin Jane F , Tuckerman J F , Henderson A R
Published: February 2014

We have modified a basic program for serum cholinesterase phenotyping using a microcomputer. This program accepts the reaction-rate result of total and inhibitor assays of activity, allows the patient to be identified and prints out a full account of the fitting process thus allowing adequate documentation. We believe that this modification enhances the usefulness of the program to laboratories engaged in the routine determination of serum cholinesterase phenotyping.
Direct Determination of Calcium and Magnesium in Serum Using Flow-Injection Analysis and Atomic Absorption Spectroscopy
Authors: Rocks Bernard F , Sherwood Roy A , Riley Clifford
Published: February 2014

The use of flow-injection analysis for the direct determination of calcium and magnesium in blood serum and plasma is described. An inexpensive rotary valve is used to inject the serum sample (4 μl) into a flowing non-segmented stream of reagent which carries the sample slug through a long narrow-bore coil—where it gradually disperses—and into the nebuliser of an atomic absorption spectrometer. This on-stream sample dilution removes the need for predilution of the sample. The resulting absorbance signals are recorded as peaks less than 40 seconds after sample injection. Analytical recoveries and precision are good for both elements and the results by flow-injection analysis compare well with established routine methods.
A Re-Examination of the Incidence of Circulating Immune Complexes in Normal Pregnancy
Authors: Kilpatrick David C , Weston James
Published: February 2014

Circulating immune complexes were detected in 20% of serum samples from pregnant patients by the liquid-phase C1q-binding assay. Two other immune complex assays yielded negative results with the same samples. A careful case study was also carried out in which serum samples from before, during and after a normal pregnancy were analysed. The results are discussed in relation to the contradictory data previously published in this field.
Iron Deficiency in a Northern Thai Population: The Effects of Iron Supplements Studied by Means of Plasma Ferritin Estimations
Authors: Linpisarn S , Thanangkul O , Suwanraj C , Kaewvichit R , Kricka L J , Whitehead T P
Published: February 2014

Iron deficiency is a common problem, particularly in developing countries, but traditional laboratory methods of detecting this condition are unreliable. The prevalence of iron deficiency in a Northern Thai population (pre-school, school children, adult women) has been assessed by means of plasma ferritin concentrations. The results were compared with prevalences based on blood haemoglobin concentrations. Estimations of prevalences based on plasma ferritin values were 10–24% in non-vegetarian and 49–71% in vegetarian groups, whilst those based on blood haemoglobin were 11–21% (non-vegetarian) and 24–50% (vegetarian). Dietary supplementation with iron produced dramatic rises in plasma ferritin in all of the groups studied. The effects on blood haemoglobin concentration and haematocrit were less marked. These results highlight the extent of iron deficiency in a Thai population and demonstrate the sensitivity of plasma ferritin as a test for detecting this condition and assessing the response to dietary supplementation.
A Monoclonal Antibody-Based Immunoradiometric Assay for h-LH
Authors: Hunter W M , Bennie J G , Kellett H A , Micklem L R , Scott A , James K
Published: February 2014

An immunoradiometric assay (IRMA) for h-LH based upon an 125I-labelled mouse monoclonal antibody (MAb) to h-LH with an effective equilibrium constant of 5·8 × 109 l/mol is described. A total incubation time of 3 h at room temperature was required, separation by means of the sucrose layering procedure took a further 1 h and counting times were 1 min/tube. Using the first IRP for h-LH (prep. 68/40) as standard, the detection limit was 0·1 U/l serum and the within-assay CV for duplicate determinations was <10% over the range 1–280 U/l and <3% at 10–100 U/l. The epitope, with which the MAb reacted, shared structures, on the α- and β-subunits of LH since the assay responded to the intact hormone, but not to either of the subunits. Specificity was > 100 000:1 for h-LH vs. h-FSH and > 10 000:1 for h-LH vs. h-TSH. h-CG and h-LH were approximately equipotent. The results on 604 unselected samples were generally very similar to those found by RIA except at levels below 2 U/l for which the IRMA regularly gave lower results suggesting relative freedom from non-specific serum effects.

The new assay, based upon potentially limitless supplies of a very stable reagent offers advantages of speed, sensitivity, range, and precision over conventional RIA. The specificity appears to be excellent. Although there are marginally more steps the total staff involvement is less than with conventional methods employing centrifugation.
The Measurement of Urinary LH, by a Solid-Phase Chemiluminescence Immunoassay
Authors: Brockelbank J L , Kim J B , Barnard G J , Collins W P , Gaier B , Kohen F
Published: February 2014

Ovulation in women may be predicted or detected by a simple, solid-phase, chemiluminescence immunoassay for the measurement of urinary LH. An IgG fraction of a donkey antiserum to rabbit immunoglobulins is passively adsorbed to the walls of polystyrene tubes. Human chorionic gonadotrophin-succinyl-butyl-ethyl-isoluminol and a primary antibody (rabbit anti-human LH) is incubated with samples of early morning urine. After the binding reaction, the solution is removed by aspiration. The antibody-bound fraction is washed twice with buffer. Sodium hydroxide is added and the mixture incubated. After cooling, luminescence is initiated by oxidation of the label with microperoxidase/hydrogen peroxide and the signal integrated.

The method has been evaluated in terms of sensitivity, within- and between-batch precision, bias and parallelism. The time interval between the peak day of LH in EMU and maximum follicular diameter during 38 menstrual cycles was −24 h (11%), 0 h (50%), + 24 h (28%) and + 48 h (11%).
Sensitive and Specific Morphine Radioimmunoassay with Iodine Label: Pharmacokinetics of Morphine in Man after Intravenous Administration
Authors: Moore R A , Baldwin D , Allen M C , Watson P J Q , Bullingham R E S , McQuay H J
Published: February 2014

Analysis of morphine in plasma by radioimmunoassay is complicated by interference from morphine metabolites, particularly morphine-3-glucuronide. This interference makes radioimmunoassay a poor technique to study the pharmacokinetics of morphine in man. The method described here is one which uses commercially available anti-morphine antiserum and separating reagent with a simply prepared iodinated morphine derivative. Cross-reactivity to morphine metabolites is negligible and the method correlates well with HPLC. Results obtained for pharmacokinetic parameters after intravenous administration in man are in agreement with published data using GLC or HPLC. The method is inexpensive, simple and rapid; choice of a different antiserum could allow the method to be used for screening for drugs of abuse such as morphine, diamorphine, codeine and dihydrocodeine.
Antigen Binding in the Two-Site Immunoradiometric Assay for Serum Ferritin: The Nature of the Hook Effect
Authors: Perera Praemi , Worwood Mark
Published: February 2014

The two stages of a two-site immunoradiometric assay were investigated separately. In the first stage, the amount of ferritin bound to coated tubes initially showed a rapid increase with increasing concentration of added ferritin. This was followed by a plateau and then a further increase which appeared to be largely due to non-specific binding. During the second stage, a significant proportion of the bound ferritin dissociated from the solid phase and sequestered some of the labelled antibody in solution. Thus less antibody was available to bind to ferritin attached to the tube, causing a decrease in count rate at high ferritin concentrations. The use of a monoclonal antibody for coating the tubes did not eliminate this hook effect.
Fluorometric Assay of Human Serum Carnosinase Activity in Normal Children, Adults and Patients with Myopathy
Authors: Bando K , Shimotsuji T , Toyoshima H , Hayashi C , Miyai K
Published: February 2014

A sensitive, accurate method has been established for the assay of serum carnosinase by measuring the fluorescence emitted from the L-histidine liberated on treatment with o-phthaldialdehyde. Using this method the serum values for normal adults, infants and children were measured. The mean value was very low in infants of less than 1 year old but increased with age, being almost the same in children aged 6 years or more as in adults. In adult men, the mean activity was 1·85 μmol/mL/h and in adult women it was 2·07 μmol/mL/h. Low activity was observed in patients with muscular dystrophy.
The Estimation of Serum Fructosamine: An Alternative Measurement to Glycated Haemoglobin
Authors: Hindle E J , Rostron Glenise M , Gatt J A
Published: February 2014

A method is presented for the estimation of fructosamine using a Cobas Bio centrifugal analyser. The effect of three different preparations of human serum albumin used for construction of calibration curves of 1-deoxy-1-morpholinofructose is described. The selection of serum albumin and the concentration used in the standard solutions is critical since the dose-response curve is affected differently and will therefore influence the estimated values. Normal ranges were obtained for non-diabetic subjects with normal protein status and for a group of females with reduced albumin levels due to pregnancy or oestrogen therapy. There was no significant difference between fructosamine levels in these populations. Fructosamine was also estimated in 250 patients attending a diabetic out-patient department and this correlated well with haemoglobin A1 estimated simultaneously. The method is rapid, technically simple and inexpensive and may prove to be a useful and reliable alternative to HbA1 estimation.
Some Aspects of Calcium Metabolism in a Fatal Case of Ethylene Glycol Poisoning
Authors: Simpson Elliott
Published: February 2014

Laboratory results are presented for a patient who died following ingestion of an antifreeze solution containing ethylene glycol. It was observed that the measurement of osmolality, which is of value in the early stages of ethylene glycol poisoning, may give normal results if there are many hours delay between ingestion and admission. The hypocalcaemia which frequently accompanies ethylene glycol poisoning is shown to develop over several hours.
Composition of Human Hepatic Bile
Authors: Albers C J E M , Huizenga J R , Krom R A F , Vonk R J , Gips C H
Published: February 2014

To define reference values of human hepatic bile for sodium, potassium, chloride, calcium, iron, copper, urea, creatinine, phosphate, glucose, bilirubin, cholesterol, protein, bile salts, phospholipids, ammonia, pH, Pco2, bicarbonate and osmolality, bile was obtained via a T-drain from 12 adult patients who underwent cholecystectomy. Bile of females had a higher cholesterol concentration than that of males. The saturation index, however, was not different in both groups.
The Effects of Glucose and Insulin on β-Hexosaminidase in Cultured Fibroblasts from Diabetic and Non-Diabetic Subjects
Authors: Hultberg B , Isaksson A , Kjellström T
Published: February 2014

The effects of glucose and insulin in culture medium on the release and cellular content of β-hexosaminidase were studied in fibroblast cultures obtained from patients with type II diabetes and from control subjects. The release of β-hexosaminidase was (positively) correlated to extracellular glucose concentration. The cellular activity was not influenced by glucose. Insulin had no effect on the cellular activity or the release of β-hexosaminidase. The results were similar for both cell types. It is proposed that increased plasma levels of lysosomal hydrolases (e.g. β-hexosaminidase) from human diabetics might be due to increased release from cells exposed to elevated glucose concentrations.
Alteration of Pituitary-Thyroid Function in Patients with Chronic Renal Failure Treated by Haemodialysis or Continuous Ambulatory Peritoneal Dialysis
Authors: Ross R J M , Goodwin F J , Houghton B J , Boucher B J
Published: February 2014

Pituitary-thyroid function was investigated in 60 patients with chronic renal failure and 18 normal subjects. Serum triiodothyronine and free thyroxine levels were lower in patients treated by either haemodialysis or continuous ambulatory peritoneal dialysis compared with the normal subjects. Serum thyroxine and free thyroxine index were significantly lower in the haemodialysis-treated patients than in the normal subjects. There were no differences in serum thyroxine and free thyroxine index between the continuous ambulatory peritoneal dialysis-treated and normal groups. Serum thyrotrophin was not raised in any of the groups but the serum thyrotrophin response to thyrotrophin-releasing hormone was blunted in both groups of patients. Basal serum prolactin and growth hormone were raised in both groups of patients but there was no significant difference between them. This study confirmed that pituitary-thyroid function is abnormal in patients receiving haemodialysis and established that a similar pattern of abnormalities occurs in patients undergoing continuous ambulatory peritoneal dialysis.
Plasma Bile Salt Levels in Patients Presenting with Generalised Pruritus: An Improved Indicator of Occult Liver Disease
Authors: Lawrence C M , Strange R C , Scriven A J , Wood A , Beckett G J
Published: February 2014

Fasting plasma bile salt concentrations were measured in 26 patients presenting to a Skin Department who had generalised pruritus without primary skin disease, as part of a screening investigation for systemic causes of pruritus. The results were compared with conventional tests of hepatic function. Plasma-conjugated cholate measurements identified all patients with hepatobiliary disease. Conventional liver function tests were abnormal in these patients but also in five patients with no other evidence of hepatic dysfunction. Fasting conjugated-cholate measurements offer a useful screening test for identifying hepatobiliary disease in patients presenting with generalised pruritus.
Liquid Control Materials for Haemoglobins A2 and F: A One-Year Interlaboratory Evaluation
Authors: Franzini Carlo
Published: February 2014

Stabilised haemolysates, to be stored at −20°C in the liquid state, have been evaluated in an interlaboratory trial: haemoglobin A2 and haemoglobin F levels were stable for at least 1 year. Since the materials can be very easily prepared in each laboratory, they appear to meet the requirements for use in internal quality-control schemes, for the assay of both haemoglobin fractions.
Comparison of Three Different Assay Procedures for the Determination of HbA1 with Special Attention to the Influence of Pre-HbA1c, Temperature and Haemoglobin Concentration
Authors: Kortlandt W , Van Rijn H J M , Hoeke J O O , Thijssen J H H
Published: February 2014

Three different methods for the measurement of glycated haemoglobin or HbA1, based on agar gel electrophoresis, ion-exchange and affinity chromatography were compared. All three showed acceptable precision (overall CV being less than 5%) and correlated well with each other ( r> 0·945). The ion-exchange and affinity chromatography method proved to be independent of the amount of pre-HbA1c present. The electrophoresis method was independent of temperature in contrast to the other two methods, which shewed a strong and comparable temperature dependency. All three methods were dependent on the haemoglobin concentration and/or protein content of the haemolysate. Both ion-exchange and electrophoresis showed significant interference by changes in haemoglobin concentrations, whereas the protein concentration significantly biased the affinity chromatography figures. Taking into account their specific merits all three methods are acceptable for routine use.
Validity of the Consensus Mean as the Target Value for a Small External Quality Assessment Scheme
Authors: Georges R J
Published: February 2014

Data from 2 years' operation of an External Quality Assessment Scheme covering 14 analytes and with some 60 participants is presented. Following the trimming of discrepant results and statistical ‘outliers' (outside the range of ±3 SD from the mean), there was generally close agreement between consensus mean values for a specimen analysed on different occasions, by different groups of laboratories, or when using different analytical methods. An improvement in performance, indicated by a reduction in the average inter-laboratory coefficient of variation was found for 11 of the 14 analytes over the 2-year period.
Insensitivity of Erythrocyte 2,3-Bisphosphoglycerate to Changes in Extracellular Phosphate Concentration in Vitro
Authors: Ryall R G , Ellis R H , Wenzel A K
Published: February 2014

Erythrocytes maintained in vitro under controlled conditions at pH 7·40 were unable to respond to changes in extracellular phosphate concentrations with changes in intracellular 2,3-bisphosphoglycerate content over an 8 h incubation period. Increased extracellular phosphate concentrations did not retard the rate at which 2,3-bisphosphoglycerate concentrations fell when erythrocytes were incubated at pH 7·10. Elevated extracellular phosphate concentrations did not increase the rate of recovery of intracellular 2,3-bisphosphoglycerate concentrations when erythrocytes were returned to pH 7·40 having been incubated at pH 7·10. The rate at which 2,3-bisphosphoglycerate concentrations increased under these latter conditions was too slow to counterbalance any effect that adjustment of blood pH may have on the position of the haemoglobin–oxygen dissociation curve during treatment of diabetic ketoacidosis.
The Determination of Glucose and Glycosylated Haemoglobin in a Non-Diabetic Zimbabwean African Population
Authors: Gomo Z A R
Published: February 2014

Reference intervals for plasma glucose and glycosylated haemoglobin A1 (HbA1) have been established in a Zimbabwean population aged 19–65 years. The subjects were a volunteer group of 777 people (440 male and 337 female). There was no significant difference in the glucose levels between men and women and the range was 2·58–5·62 mmol/L. There was, however, a significant difference in the HbA1 levels between men and women ( P < 0·001); the ranges found were: men, 4·86–9·78%; women, 4·30–8·22%. On comparison between HbA1 in the Zimbabwean population and published results a statistically significant difference was observed ( P > 0·002). This study highlights the importance of determining reference intervals for each sex and ethnic group.
Dried Blood Spot Test Estimation of Urea
Authors: Plumbe R M , Worth H G J
Published: February 2014

The analysis of urea in serum and whole blood samples dried onto filter paper has been investigated. In both cases the sample volume is not critical nor is the volume of sample applied to the filter paper if sample discs of consistent dimensions can be punched from the dried paper. The method must be calibrated by a serum-based material not an aqueous standard, presumably because of a matrix effect. A coefficient of variation of approximately 6% has been achieved over a wide range of urea concentration and the method has been shown to correlate well with a standard laboratory procedure. The technique has a particular application to neonatal capillary samples.
Changes in Erythrocyte Transketolase Activity and the Thiamine Pyrophosphate Effect during Storage of Blood
Authors: Puxty J A H , Haskew A E , Ratcliffe J G , McMurray J
Published: February 2014

Whole blood and washed erythrocytes from nutritionally normal and abnormal elderly patients were stored at room temperature, 4°C and −20°C for up to 14 days. In both groups, and under all storage conditions, the erythrocyte transketolase (ETK) activity and the thiamine pyrophosphate (TPP) effect decreased with time of storage. The ETK activity for specimens stored at −20°C decreased significantly by day 14 ( P < 0·05). The TPP effect in specimens stored at −20°C decreased significantly in the nutritionally abnormal group at 4 days ( P < 0·05) and in the nutritionally normal group by day 14 ( P < 0·05). These significant changes in ETK activity and TPP effect with storage can lead to misleading interpretation of thiamine nutritional status.
The Measurement of High Density Lipoprotein Subtractions in Patients with Primary Gout Using a Simple Precipitation Method
Authors: Ferns G A A , Lanham J , Stocks J , Ritchie C , Katz J , Galton D J
Published: February 2014

We have evaluated a simple dextran sulphate precipitation method for measuring high density lipoprotein cholesterol (HDL) subfractions and have used this method to measure plasma HDL2 and HDL3 in a group of 28 patients with primary gout. These patients were found to have significantly lower levels of plasma HDL and HDL2 than a group of healthy controls, matched for age and sex and of similar body mass index (BMI); no significant difference in mean levels of the HDL3 subtraction was found however. We have confirmed the high prevalence of hypertriglyceridaemia in subjects with gout compared to controls and the mean serum triglyceride levels were significantly higher ( P < 0·01) in the gout group than in controls. We have also shown that subjects with high serum triglyceride levels tend to have low plasma HDL2 concentrations, a finding which is consistent with an inverse relationship between these two parameters. These lipid abnormalities may partly explain the high prevalence of premature atherosclerosis in patients with primary gout.
Measurement of Copper, Zinc and Magnesium in Serum and Urine by DC Plasma Emission Spectrometry
Authors: Roberts N B , Fairclough D , McLoughlin S , Taylor W H
Published: February 2014

The application of a DC plasma emission spectrometer to the measurement of copper, zinc and magnesium in serum and urine is reported. Each assay requires only a simple dilution in 1% nitric acid.

Comparisons with standard atomic absorption techniques showed good analytical agreement, especially for copper and magnesium. Analysis of quality control preparations for copper and zinc gave results ranging from −1·5% to +3·6% of the stated values for five copper and four zinc experiments, with an unexplained result of +7·6% for one zinc experiment. Reference ranges were compiled for serum zinc and urinary copper which agreed closely with those established by atomic absorption and neutron activation analysis. Assays by DC plasma emission are thus precise and reproducible, and simple enough to authenticate the method for use in a clinical laboratory.
Therapeutic Monitoring of the Anti-Anginal Drug Perhexiline Maleate
Authors: Cooper J D H , Turnell D C , Pilcher J , Lockhart D
Published: February 2014

Patients taking oral doses of perhexiline maleate have been examined. Measurement of serum perhexiline concentrations established that different dose requirements between patients were necessary due to the different doses at which drug saturation was achieved. Measurement of serum perhexiline concentrations are essential if side-effects from the drug are to be avoided.
Methods of Assigning Accurate Values to Reference Serum. Part 1. The Use of Reference Laboratories and Consensus Values, with an Evaluation of a Procedure for Transferring Values from One Reference Serum to Another
Authors: Broughton P M G , Eldjarn L
Published: February 2014

A method is described for transferring the accuracy of values obtained by reference laboratories from one serum, which is used as a calibration standard, to another, which is treated as the unknown test sample. Six batches of lyophilised horse serum, of closely similar composition, were analysed by 10 European reference laboratories during 1978–1982, and used to obtain transfer values for one masterlot of a similar serum. No evidence was found that the transfer process introduced any inaccuracy. A comparison has been made, for bilirubin, creatinine, iron, phosphate, total protein and urea, between transferred values, the results obtained by direct analysis of the masterlot by reference laboratories, and consensus values found in two independent external quality assessment schemes. The transfer technique enables an evaluation to be made of these different procedures for assigning values to reference serum, and may reveal methodological differences, such as those described for iron and creatinine.
Drug Screening: Evaluation of the Toxi-Lab TLC System
Authors: Jarvie D R , Simpson D
Published: February 2014

An evaluation of a commercial TLC Kit System (Toxi-Lab®) is described. The performance of the system is assessed in the detection of drugs in overdose and in therapy, and is compared with a GC drug screening system.

Toxi-Lab performed well in investigating drug overdoses. We found data on metabolite patterns essential for the identification of drugs in urine and for this reason the system performed much better than GC screening in which information on metabolites is limited. In our experience Toxi-Lab screening was not sufficiently sensitive for the detection of commonly prescribed psychiatric drugs taken in therapeutic doses.

This system is rapid, versatile and suitable for small laboratories, but is comparatively expensive and some expertise is necessary to interpret results. A major deficiency of the kit is that the identification procedures are designed for the detection of drugs available in the USA and many drugs prescribed in the UK have been omitted.
Effect on Biochemical Values of Heat Treatment of Plasma for the Safe Handling of Samples from AIDS Patients
Authors: Collinson P O , Stein P E , Light P K
Published: February 2014

There is widespread concern amongst laboratory workers over the risks of exposure to human T cell lymphotrophic virus III [HTLV III] and the possibility of the subsequent development of the acquired immune deficiency syndrome [AIDS]. HTLV III is thermolabile and is completely inactivated by heating at 56°C for 30 min.1 We have studied the effect that such heating would have on analyses performed routinely in our laboratory.
Whole Blood Osmolality
Authors: Rocks B F , Sherwood R A , Cook J G H
Published: February 2014

The osmolality of plasma and heparinised whole blood samples collected from hospital patients was estimated using measurement of the depression of freezing point. There was no clinically significant difference between osmolality measurement made on either whole blood, or plasma taken from the same patient. Neither cell volume nor haemolysis was found to affect the measurement. The reproducibility of whole blood measurements was similar to that for determinations carried out on plasma. Measurement of osmolality on whole blood is quicker and cheaper and needs a smaller specimen than if serum or plasma is used.
Reduced Serum Carnosinase Activity in Hypothyroidism
Authors: Bando Keiichi , Ichihara Kiyoshi , Shimotsuji Tsunesuke , Toyoshima Hiroyuki , Koda Kazuma , Hayashi Chozo , Miyai Kiyoshi
Published: February 2014

Carnosinase hydrolyses carnosine in muscle, and its deficiency is associated with extensive neuromuscular abnormalities. We measured serum carnosinase activity in patients with thyroid dysfunction which often involves neuromuscular systems. In hyperthyroidism, the carnosinase activity was not significantly different from that in normal subjects. In hypothyroidism, however, it was significantly lower than that in normal subjects. The activity examined in five patients with hypothyroidism returned to normal after replacement therapy. In hypothyroidism, the carnosinase activity showed significant correlation with concentration of serum thyroxine and negative correlation with serum creatine kinase activity. This finding may be of practical importance in the differential diagnosis of disorders causing carnosinase deficiency.
Screening for Early Diabetic Nephropathy
Authors: Marshall S M , Alberti K G M M
Published: February 2014

An albumin excretion rate of 30–150 μ/min is a strong predictor of future clinical diabetic nephropathy. The collection of urine samples commonly used is cumbersome and tedious for both patients and laboratory staff. We have therefore examined the usefulness of albumin:creatinine ratio measurement as a predictor of albumin excretion rates greater than 30 μg/min. Values above 3·5 for the albumin:creatinine ratio gave high sensitivity (98%) but low specificity (63%) while a value greater than 4·5 had a sensitivity of 96% and specificity of 72%. We conclude that the albumin:creatinine ratio in a first morning urine sample is useful as an initial screening test for microalbuminuria but that further analysis is required to select those with definite microalbuminuria.
Measurement of Serum α1-Antichymotrypsin by Immunoturbidimetry
Authors: Calvin J , Price C P
Published: February 2014

A simple, fast method for the measurement of serum α1-antichymotrypsin by an immunoturbidimetric technique is described. The assay spans the range 0·21 g/L to 2·83 g/L which covers adequately the majority of concentrations encountered in normal and pathological sera. The precision is good and the accuracy acceptable, as judged by a comparison with an electroimmunoassay technique. A reference range has been obtained using samples collected from blood donors.
Biochemical Basis for the Antagonism between Aminoglutethimide and Danazol in the Endocrine Treatment of Breast Cancer
Authors: Dowsett M , Murray R M L , Pitt P , Jeffcoate S L
Published: February 2014

Only 13% of postmenopausal advanced breast cancer patients responded to endocrine treatment with aminoglutethimide plus danazol whilst 33% responded to aminoglutethimide alone, despite a similar suppression of serum oestradiol levels in the two groups. The patients on aminoglutethimide and danazol showed a marked suppression of sex hormone binding-globulin binding capacity and a consequent rise in percent-free oestradiol. This led to the concentration of free oestradiol being less well suppressed than that of total oestradiol and in some patients free oestradiol concentrations were higher on treatment than before. Patients on aminoglutethimide alone showed no change in the binding of oestradiol and the percentage suppression of the free oestradiol concentration was similar to that of total oestradiol. The opposing effects of danazol and aminoglutethimide on the concentration of the free, biologically active fraction of oestradiol in the circulation may explain the poor therapeutic efficacy of this combination in breast cancer patients.
Seasonal Variations in Haematological and Biochemical Parameters
Authors: Gidlow David A , Church John F , Clayton Barbara E
Published: February 2014

Biochemical and haematological data obtained over five consecutive years are presented on the male workforce of a large chemical company. The data have been subjected to statistical analysis and quantify the influence of age and the month of the year in which the samples were taken. The red cell count, white cell count, serum γ-glutamyl transferase, alanine transaminase and creatinine show significant and consistent seasonal variations. The previously published work on the influence of age on several indices is confirmed. Biochemical screening may be a method of detecting early signs of toxicity in man but such factors as age, sex and season must be taken into account when comparing the results obtained from exposed and non-exposed groups.
Determination of Cobalt in Urine by Flameless Atomic Absorption Spectroscopy. Comparison of Direct Analysis Using Zeeman Background Correction and Indirect Analysis Using Extraction in Organic Solution
Authors: Bouman A A , Platenkamp A J , Posma F D
Published: February 2014

Urinary cobalt was determined by flameless atomic absorption spectroscopy. Three methods were compared: (i) direct analysis with deuterium background correction after 11-fold dilution with distilled water (method D), (ii) analysis with deuterium background correction after extraction of cobalt from the urinary matrix in organic solution (method E), and (iii) direct analysis with Zeeman background correction (method Z). The detection limit of the direct analysis of urinary cobalt with deuterium background correction was 6 μg/L, this appeared to be insufficient for the determination of reference values and moderate enlarged cobalt values. Comparison of the extraction method and the Zeeman method revealed that these methods have similar reference values, detection limits, precision and recovery.
Alkaline Phosphatase and Cholestasis
Authors: Wulkan R W , Leijnse B
Published: February 2014

The process of cholestasis in both man and rat leads in the majority of cases to the appearance of a biliary band in the electrophoresis of alkaline phosphatase isoenzymes. In this article, the biochemical nature and mode of formation of the biliary band is discussed, with reference to its appearance in cholestasis and other hepatobiliary diseases.
Glycosylated Haemoglobin by Affinity Chromatography in Diabetic and Non-Diabetic Children
Authors: Van Heyningen C , Hanid T K , Hopkinson I
Published: February 2014

We have made an evaluation of glycosylated haemoglobin measurements by affinity chromatography in a paediatric population. Age-related reference values for non-diabetic infants and children are reported. A poor correlation ( r=0·24) was found between glycosylated haemoglobin values in 26 insulin-dependent diabetic children and the paediatrician's independent assessment of clinical control.
A Rapid HPLC Method for Monitoring Plasma Levels of Caffeine and Theophylline Using Solid Phase Extraction Columns
Authors: Pickard Clare E , Stewart A D , Hartley R , Lucock M D
Published: February 2014

A simple HPLC method for the determination of caffeine and theophylline in plasma is described. Separation of theobromine, paraxanthine, theophylline, β-hydroxyethyltheophylline and caffeine is obtained using a mobile phase of 1% acetic acid/methanol (83:17, v/v) and a Waters Associates NOVA-PAK C18 column protected by a Guard-PAK precolumn module containing a Guard-PAK CN cartridge. Rapid sample preparation is achieved by solid-phase extraction columns (Bond-Elut C18, 1 mL capacity) which provide excellent recovery values for both drugs. The cost per sample using this approach can be minimised by column regeneration and re-use. Results obtained for theophylline are in good agreement with values determined by other techniques.
Effects of Workload and Analysis Time on the Cost of Out-of-Hours Investigations
Authors: Gunn I R , Little A J , Payne R B
Published: February 2014

In the UK, under present Whitley Council Regulations for payment for out-of-hours pathology services, there is a complex relationship between the number of requests received, the time taken to analyse each request, and the number of calls for which payment may be claimed for work done. At a fixed average analysis time, the rate of increase of remuneration slows down as workload increases until at higher workloads remuneration falls. The introduction of methods with a shorter average analysis time to improve the clinical service increases remuneration disproportionately. We suggest that a fixed sessional payment would be a better way of funding the service.
An Improved Method for Measurement of Common Tricyclic Antidepressant Drugs and their Metabolites Using Normal Phase HPLC
Authors: Blakesley J D , Howse C G , Spencer-Peet J , Wood D C F
Published: February 2014

A sensitive HPLC method that allows the simultaneous determination of imipramine, amitriptyline and their desmethyl metabolites, using a 10 cm straight silica cartridge column with a mobile phase consisting of 0·004% perchloric acid in methanol is presented. Detection of the eluent is at 210 nm. The drugs are back-extracted from serum, giving both a good recovery and sensitivity of at least 5 μg/L.

This method has proved to be extremely robust and reliable, with coefficients of variation around 3% being reported.
Ideas towards a General Theory of Clinical Biochemistry
Authors: Baron D N
Published: February 2014

Clinical biochemistry, as an independent discipline within medical science, has developed its own body of theory and practice, and as such it cannot only be concerned with collecting observations. A simple report (plasma potassium=5·3 mmol/L*) is used as a model to discuss the problems of understanding measured chemical changes in the body in disease, and how these lead towards a general theory. These include the nature of the analysand and the reference base; accuracy and identification of the analyte; how disturbances of the steady state contribute to changes in a static result; the implications of precision; differences between activity, concentration and content; the convention of arithmetical concentration; and the meaning of ‘abnormal’, and of derived terms such as ‘predictive value’ and ‘decision level’. Clinical biochemists/chemical pathologists, with their understanding of all these and related problems, must act as the necessary bridge between analysts and clinicians.
Plasma Alkaline Phosphatase Activity and its Relation to Rickets in Pre-Term Infants
Authors: Walters E G , Murphy J F , Henry P , Gray O P , Helder G
Published: February 2014

Sequential measurements of plasma alkaline phosphatase activity were made in 84 pre-term infants delivered before 38 weeks gestation. In 67% of infants, without evidence of rickets but in whom three or more measurements were made and the peak activity was less than 10 times the adult reference range, the activity rose to a peak and declined to previous levels, or lower. The time taken for these changes varied greatly. The range of values was inspected at each week of age, and in all but six cases the level did not exceed 10 times the upper limit of the adult reference range. Three infants had radiological evidence of rickets, and of the six cases in whom higher levels were found, only one had radiological evidence of rickets; the remainder did not. It is recommended that in the latter, the high plasma alkaline phosphatase activity should be regarded as evidence of subclinical bone disease.
N-Acetyl-β-D-Glucosaminidase Enzymuria in Leukaemia and Myelomatosis: Effect of Treatment in Acute Myeloblastic Leukaemia and Myelomatosis in Adults
Authors: Whiting P H , King D J , Ireland A , Ratcliffe M A , Dawson A A
Published: February 2014

The activity of the lysosomal hydrolase N-acetyl-β-d-glucosaminidase (NAG) was measured in the urine of patients with leukaemia or myeloma. Elevated pre-treatment enzymuria was noted in all patient groups with acute myeloblastic leukaemias (AML) FAB type M4 or 5 displaying higher activities than AML patients FAB types M1–3, which in turn were higher than those found in patients with myelomatosis and chronic lymphocytic leukaemia. The ratio of the major isoenzymes of NAG, A/B was reduced significantly only in patients with AML. Following treatment, AML patients who entered remission demonstrated NAG levels which approached normal values. In those AML patients who were either in relapse, in the terminal phase of their illness or treated with aminoglycoside antibiotics, NAG enzymuria was similar to pre-treatment values. A reduction in urinary NAG levels and both serum and urine β2 microglobulin concentrations was also observed following treatment in myeloma patients. The use of enzymuria both as a guide to progress towards remission in AML patients and for assessing prognosis and progress in myeloma patients is discussed.
Improved Measurement of Monoclonal Paraproteins in Serum Using Agarose Gel Electrophoresis
Authors: Dennis P M , Biegler B , Papas R
Published: February 2014

Serum paraproteins can be accurately and precisely measured by means of agarose gel electrophoresis and densitometry at 520 nm after staining with Coomassie Brilliant Blue G. The results obtained for this method agree closely with the quantity of paraprotein recoverable from preparative agarose gel electrophoresis. The method is preferable to cellulose acetate electrophoresis stained with Ponceau S.
Strategies to Modify the Test-Requesting Patterns of Clinicians
Authors: Fraser C G , Woodford F P
Published: February 2014

Studies of the effectiveness of various strategies for influencing clinicians' test-requesting behaviour are reviewed. Numerical rationing, although crude, effectively reduces unnecessary repeat testing without detriment to patient outcome. Educational programmes involving peer review show pronounced but short-lived effects. Simple feedback of information about numbers of tests requested and their costs is surprisingly ineffectual. Direct financial incentives, in a private health care system, also failed. Clinical budgeting, of benefit in experimental trials, has yet to be widely tested, and the savings on reducing laboratory requesting may not be large enough to be attractive to clinicians. Agreed requesting policies in various specialities and clinical circumstances, endorsed by senior clinicians and prestigious professional bodies, seems a promising approach to more appropriate test requesting; further objective studies of their long-term effects are needed. Redesign of request forms into a problem-orientated format may be the simplest and most effective contribution by the laboratory; this strategy deserves further critical appraisal.
Bedside Application of an Ultrasensitive Urine Test for HCG in Patients with Suspected Ectopic Pregnancy
Authors: Buck R H , Pather N , Moodley J , Joubert S M , Norman R J
Published: February 2014

One hundred and seven patients with suspected ectopic pregnancy were tested for HCG at the bedside using the Tandem Icon. The test was performed by ward doctors with no formal laboratory experience. The patients were managed conservatively or by surgery as dictated by the clinical picture and the Icon test result. Retrospective categorisation of the 107 patients by laboratory analysis and clinical outcome showed that 21 were pregnant (17 ectopic, 4 intrauterine) and 86 non-pregnant. At the bedside the Icon was reported as negative in one pregnant patient and three patients who were not pregnant were found to give Icon-positive results. In the laboratory the Icon correctly categorised all patients. Three of the four discrepant results were found to be a direct result of the operator's inexperience in analytical procedure and interpretation. The Tandem Icon HCG urine assay can reliably be used at the bedside of patients with suspected ectopic pregnancy provided that the operator has had sufficient experience in its use.