bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Glycated Haemoglobin in whole Blood by a Novel Fluorescence Quenching Assay
Authors: Blincko Stuart , Anzetse Judith , Edwards Raymond
Published: February 2014

We describe a method for the specific measurement of glycated Hb (GHb) by fluorescence quenching. Whole blood is added to lysing solution, then the lysate is mixed with eosin-boronic acid solution and reacted for at least 5 min at room temperature. The quenching of the fluorescence of the eosin-boronic acid solution is proportional to the concentration of GHb present. Total Hb concentration was measured by absorbance and the GHb expressed as a percentage of the total Hb. Comparison with a commercial high-performance liquid chromatography (HPLC) system for HbA1c showed: %GHb = 1·30 (SD 0·04)%HbAlc + 1·36 (SD 0·30), Sy/x 0·803, n = 95, r = 0·965 (SD = standard deviation). Intra-assay coefficients of variation were <2·5% (for GHb concentrations in the range 6–20%) and inter-assay coefficients of variation were <4·1% (10 assays on six samples with GHb concentrations in the range 6–20%). Linearity of response was demonstrated by dilution. The effect of adding exogenous glucose, bilirubin and triglycerides was tested on samples with low, medium and high GHb concentrations. No significant interference was found. Variation of haematocrit over the range 0·4–0·6 also had no significant effect on percentage GHb. Preliminary results with samples containing variant Hb (HbAS and HbAC) indicated good agreement with HPLC for these samples also.
Measurement of Iohexol by Capillary Electrophoresis: Minimizing Practical Problems Encountered
Authors: Jenkins Margaret A , Houlihan Christine , Ratnaike Sujiva , Jerums George , Parkin J Des
Published: February 2014

Iohexol is a non-ionic contrast agent, which has been widely described in recent literature as an accurate marker for the measurement of glomerular filtration rate (GFR). Our aim was to establish a capillary electrophoresis assay, based on a previously described method, that had adequate reproducibility to be used as part of a clinical trial. In this paper, we examine the practical aspects, pitfalls and steps we took to achieve a precise and reproducible assay. To minimize laboratory variation, we examined properties such as the use of an internal standard in a capillary electrophoresis separation, alternative deproteinization methods for serum, the most suitable matrix for the dilution of standards and the implementation of suitable quality control material to ensure that run-to-run variability was minimized. The optimized capillary electrophoretic assay of iohexol was found to be robust, with over 860 runs from the one capillary over a 9-month period. Excluding capital costs of the instrument, the consumable cost of the assay is less than AS0·25 per test, with a run time of 5·25 min and a coefficient of variation (CV) of 4·3% at 80 mg/L. The GFR, calculated from the plasma clearance, had a reproducibility of 5·47%.
Assessment of Adult Phenylketonuria
Authors: Cleary Maureen , Walter J H
Published: February 2014

Phenylketonuria (PKU) has been detected on the newborn screening programme since the 1960s. Although it is recognised that dietary treatment is successful in avoiding the severe mental retardation associated with untreated PKU, the long-term outcome for adults remains unclear. The Medical Research Council recommends that the diet be followed for life. This paper discusses the relevance of the findings of neurological deterioration, neuropsychological problems and brain imaging in adults with PKU. It suggests an approach to follow-up for adults with PKU including neurological assessments, awareness of nutritional deficiencies, educational requirements and the risks of maternal PKU.
Diagnosis and Clinical Biochemistry of Inherited Tubulopathies
Authors: Sayer J A , Pearce S H S
Published: February 2014

Epithelial ion channels and transporter proteins have physiologically important roles throughout the length of the nephron. Discovering the molecular identities of tubular epithelial cell proteins and their functional roles has increased understanding of both renal physiology and tubular diseases. Defects in tubular handling of solutes may present with nephrocalcinosis or nephrolithiasis, rickets, acid-base, electrolyte or blood pressure disturbances. Biochemical analysis of both serum and urine, together with clinical history and examination, remain fundamental for their diagnosis, whilst understanding of underlying molecular mechanisms allows appropriate management.
Growth Hormone: Its Measurement and the Need for Assay Harmonization
Authors: Wood Peter
Published: February 2014

Serum human growth hormone (hGH) assays show a wide range in bias and in cut-off values for provocative tests, which vary from 13·5 to 35–40 mU/L when they have been established. Studies using novel hGH assays show that methods that are absolutely specific for 22-kDa hGH may not identify bioactive hGH peaks and that 20:22-kDa hGH ratios are increased in acromegaly. Greater harmonization of serum hGH methods can be achieved by: changing from IS 80/505 to IS 98/574, which is calibrated in mass units of recombinant 22-kDa hGH; using monoclonal/polyclonal or polyclonal/polyclonal antibody combinations that measure both 20-kDa and 22-kDa hGH; the development of assays such as the immunofunctional hGH assay which has the convenience of an immunometric assay but gives results that correlate better with bioassays; collaboration between manufacturers and laboratories to establish method-related cut-off limits for provocative tests of hGH status.
Procalcitonin as an Acute Phase Marker
Authors: Whicher John , Bienvenu Jacques , Monneret Guillaume
Published: February 2014

Procalcitonin is a 14-kDa protein encoded by the Calc-I gene along with calcitonin and katacalcin. The function and regulation of this protein are quite different from those of the other gene products. Blood concentrations of procalcitonin are increased in systemic inflammation, especially when this is caused by bacterial infection. Studies of its behaviour in patients with bacterial sepsis have led to the proposal that it may be a useful marker of systemic bacterial infection, with greater specificity and sensitivity than acute phase proteins such as C-reactive protein.
Measurement of Asialylated LDL in the Blood of Patients with Coronary Artery Disease by Antibody-Lectin Sandwich Assay
Authors: McDowell A , Young I S , Wisdom G B
Published: February 2014

Elevated concentrations of asialylated LDL (asialo-LDL) have been reported in patients with coronary artery disease (CAD). This may stimulate lipid accumulation in arterial intima cells and promote atherosclerosis. To investigate asialo-LDL as a potential risk-factor for coronary atherogenesis, we developed an antibody-lectin sandwich assay to measure levels in serum from CAD patients and age-matched control subjects. LDL was captured with an anti-apolipoprotein (apo) B antibody and asialylated oligosaccharides measured using the biotinylated D-galactose (D-gal) binding lectin, Ricinus communis agglutinin 120 (RCA120), and a streptavidin-alkaline phosphatase conjugate. For the control and atherosclerotic subjects, median [interquartile range (IQR)] values for total concentrations of asialo-LDL were 240mg/L (18O–310mg/L) and 220mg/L (186–390 mg/L), respectively ( P=0·82). When expressed as a percentage of serum apo B-100, median (IQR) values were 18% (16–23%) and 19% (15–29%), respectively ( P=0·78). These results suggest asialo-LDL has little value as a risk factor for coronary atherosclerosis.
Bilirubin Measured on a Blood Gas Analyser: A Suitable Alternative for Near-Patient Assessment of Neonatal Jaundice?
Authors: Peake Michael , Mazzachi Beryl , Fudge Andrew , Bais Renze
Published: February 2014

The reliability of a recently released total bilirubin assay for a blood gas analyser was assessed in two Australian hospital laboratories. The instrument computes total bilirubin concentration from multi-wavelength absorbance measurements of undiluted whole blood or plasma. Performance of the Radiometer ABL 735 blood gas analyser bilirubin method (software version 3.6) was compared with a proven Roche diazo method for Hitachi analysers, calibrated using primary standards prepared from NIST SRM 916a bilirubin. Acceptable bilirubin results were found over a wide concentration range for most neonatal samples of whole blood or plasma. For adult specimens, bilirubin results were approximately 10% lower on the blood gas analyser. Within-run imprecision (whole blood) was <2·5%, between-day imprecision (synthetic controls) <1·0%, and the bilirubin assay for both whole blood and plasma was linear to 1000μmol/L. Using sampling options from 35 μL to 195μL, bilirubin results differed by less than 3%, with a 95 μL syringe option producing the highest results. We conclude that the Radiometer ABL 735 bilirubin assay is suitable for near-patient assessment of neonatal jaundice using whole blood, thus eliminating the need for sample centrifugation. Verification using laboratory methods can be used when required. A positive correction of approximately 10% is required for adult specimens to conform with Hitachi results (SRM 916a calibration), possibly due to the optical characteristics of the higher proportion of conjugated bilirubin and other substances present in most adult samples.
Measurement of Pyruvate in Blood by High-Performance Liquid Chromatography with Fluorescence Detection
Authors: Wulkan Raymond W , Verwers Renée , Neele Marjolein , Mantel Mart J
Published: February 2014

Accurate measurement of pyruvate is particularly important in the detection of mitochondrial enzyme disorders. We describe a simple high-performance liquid chromatography assay for pyruvate with derivatization and fluorescence detection. Between-run variation is below 4·5% and the method is linear between 1 and 1200μmol/L. The mean recovery is 101%. After sample pretreatment, the calculated pyruvate concentration proved to be stable for 15 days when samples were kept at −20°C.
IgD Myeloma: A Potential Missed Diagnosis
Authors: Sinclair David , Cranfield Tanya
Published: February 2014

This report describes a case of IgD lambda myeloma which was discovered only following investigation of a suspicious ‘low gamma region’. If anti-IgD investigations had not been carried out, it may have been misinterpreted as Bence Jones myeloma. The case illustrates that evaluation of serum and urine in cases of suspected myeloma is mandatory and that the possibility of IgD myeloma in cases that appear to be ‘free light chain’ paraproteins only should be investigated.
Combination of Analytical Quality Specifications Based on Biological Within- and Between-Subject Variation
Authors: Petersen Per Hyltoft , Fraser Callum G , Jørgensen Lone , Brandslund Ivan , Stahl Marta , Gowans Elizabeth MS , Libeer Jean-Claude , Ricós Carmen
Published: February 2014

At a conference on ‘Strategies to Set Global Analytical Quality Specifications in Laboratory Medicine’ in Stockholm 1999, a hierarchy of models to set analytical quality specifications was decided. The consensus agreement from the conference defined the highest level as ‘evaluation of the effect of analytical performance on clinical outcomes in specific clinical settings’ and the second level as ‘data based on components of biological variation’. Here, the many proposals for analytical quality specifications based on biological variation are examined and the outcomes of the different models for maximum allowable combined analytical imprecision and bias are illustrated graphically. The following models were investigated. (1) The Cotlove et al. (1970) model defining analytical imprecision (%CVA) in relation to the within-subject biological variation (%CVw-s) as: %CVA≤ 0·5 × %CVW-S (where %CV is percentage coefficient of variation), (2) The Gowans et al. (1988) concept, which defines a functional relationship between analytical imprecision and bias for the maximum allowable combination of errors for the purpose of sharing common reference intervals. (3) The European Group for the Evaluation of Reagents and Analytical Systems in Laboratory Medicine (EGE Lab) Working Group concept, which combines the Cotlove model with the Gowans concept using the maximal acceptable bias. (4) The External Quality Assessment (EQA) Organizers Working Group concept, which is close to the EGE Lab Working Group concept, but follows the Gowans et al. concept of imprecision up to the limit defined by the model of Cotlove et al. (5) The ‘three-level’ concept classifying analytical quality into three levels: optimum, desirable and minimum. The figures created clearly demonstrated that the results obtained were determined by the basic assumptions made. When %CVW-S is small compared with the population-based coefficient of variation [%CVp = (%CV2W-S +%CV2B-S)1/2], the EGE Lab and EQA Organizers Working Group concepts become similar. Examples of analytical quality specifications based on biological variations are listed and an application on external quality control is illustrated for plasma creatinine.
Receptor Activator for Nuclear Factor Kappab Ligand and Osteoprotegerin: Regulators of Bone Physiology and Immune Responses/Potential Therapeutic Agents and Biochemical Markers
Authors: Buckley Katherine A , Fraser William D
Published: February 2014

The discovery of receptor activator for nuclear factor kappaB ligand (RANKL) and osteoprotegerin (OPG) as the fundamental factors in controlling osteoclast formation and activation has led to a greater understanding of bone biology over the past few years. Here we discuss the role of these molecules in immunology and skeletal remodelling and assess their involvement in diseases of bones and joints, including rheumatoid arthritis, Paget's disease, post-menopausal osteoporosis and malignant bone diseases. OPG has been identified as a potential anabolic agent for treating conditions in which there is net bone loss and is currently in Phase I clinical trials.

This review examines the current evidence indicating that OPG increases bone mass, and discusses other possible beneficial effects of OPG, such as inhibition of tumour growth and relief from bone cancer pain. OPG can be measured in human serum, and numerous studies have suggested that increased or decreased serum concentrations of this molecule can indicate the existence of remodelling disorders. Here we discuss how abnomnal serum OPG concentrations could potentially be used to indicate imbalances of bone resorption and formation. The possible applications of serum OPG concentration as a marker for non-skeletal disease conditions are also considered.
Temporal Changes in Maternal Serum Biochemical Markers of Trisomy 21 across the First and Second Trimester of Pregnancy
Authors: Spencer K , Crossley JA , Aitken DA , Nix ABJ , Dunstan FDJ , Williams K
Published: February 2014

Background

Many maternal serum markers show concentration changes in Down's syndrome pregnancies but the magnitude of the change in median marker levels varies with gestation. To date these changes have not been accurately specified.

Methods

The trends in marker median levels between 6 and 20 weeks of gestation were examined for alphafetoprotein (AFP), free β human chorionic gonadotrophin (F β-hCG), total human chorionic gonadotrophin (ThCG) and pregnancy-associated plasma protein A (PAPP-A) by a meta-analysis of data obtained from our collaborative studies and routine screening programmes for Down's syndrome over a 10-year period. Data were available from between 709 and 1082 Down's syndrome pregnancies and from between 14 607 and 153 909 unaffected pregnancies for each marker. The median multiple of the median (MoM) and mean log10MoM for each marker at each completed week of gestation were estimated and the trend with gestation smoothed using a weighted least squares regression model.

Results

The gestational ages at which maximum separation of marker levels occurred, comparing affected and unaffected pregnancies, and the respective regressed median MoMs and mean log10MoMs, were: for AFP at 16 weeks, 0·72 MoM, 0·14288 log10MoM; for F β-hCG at 15 weeks, 2·24 MoM, 0·35034 log10MoM; for ThCG at 16 weeks, 1·93 MoM, 0·28548 log10MoM, as well as before 8 weeks (< 0·65 MoM, 0·18853 log10MoM); and for PAPP-A before 8 weeks, < 0·33 MoM, 0·47727 log10MoM.

Conclusion

There is significant temporal variation in mean log10MoM values for the screening markers investigated. Screening algorithms, modified to take account of this variation, should allow more accurate gestation-specific risks to be calculated in individual pregnancies.
Evaluation of Whole Blood Serotonin and Plasma and Urine 5-Hydroxyindole Acetic Acid in Diagnosis of Carcinoid Disease
Authors: Carling RS , Degg TJ , Allen KR , Bax NDS , Barth JH
Published: February 2014

Background

Carcinoid disease is an uncommon disorder resulting from tumours of the enterochromaffin cells. Current biochemical investigation usually involves the measurement of 5-hydroxyindole-3-acetic acid (5-HIAA) in 24-h urine collections. Because of the problems associated with urine collections (i.e. inconvenience, accuracy of collection and requirement for preservatives) two alternative markers, fasting plasma 5-HIAA and whole blood serotonin (5-hydroxytryptamine), have been studied.

Methods and results

Whole blood serotonin concentration and plasma and urine 5-HIAA concentrations were measured by high-performance liquid chromatography in 31 patients suspected of having carcinoid and 26 known carcinoid patients. Receiver operator characteristic curve analysis of the data showed no statistical difference between the three markers ( P>0·01) with regard to their discriminating function. However, fasting plasma 5-HIAA assay showed greater stability than whole blood serotonin assay and is more convenient for the patient than a 24-h urine collection. At a cut-off value of 118 nmol/L plasma 5-HIAA assay showed a sensitivity of 89%, a specificity of 97% and a test efficiency of 93%. Whole blood serotonin assay was further limited by its saturation in platelets at 40 nmol/109 platelets which made it less suitable for monitoring the treatment of carcinoid disease.

Conclusion

Fasting plasma 5-HIAA concentration provides a more convenient screening test for carcinoid and overcomes the problems associated with 24-h urine collections, without any loss of diagnostic precision.
Assay of Catechol-O-Methyltransferase Activity in Human Erythrocytes Using Norepinephrine as a Natural Substrate
Authors: Masuda Mayumi , Tsunoda Makoto , Yusa Yukie , Yamada Shizuo , Imai Kazuhiro
Published: February 2014

Background

Catechol- O-methyltransferase (COMT) catalyses the inactivation of catecholamines. It is widely distributed in most tissues in soluble (S-COMT) and membrane-bound (MB-COMT) forms. Recently, we used a new assay for COMT activity and demonstrated that COMT plays an important role in blood pressure regulation in spontaneously hypertensive rats. In order to investigate whether this is true for human hypertension, we have evaluated the erythrocyte COMT assay in humans.

Method

The assay procedure included the use of norepinephrine (NE) as a natural substrate and the quantification of the reaction product, normetanephrine, followed by high-performance liquid chromatography separation and fluorescence or chemiluminescence detection.

Results

After evaluation of the method, the optimum conditions were obtained for the assay of human erythrocyte COMT. The S- and MB-COMT activities obtained were 50·6 (24·5) and 329·8 (179·4) fmol/min/mg protein, respectively [mean (standard deviation); n = 54]. The Km values for NE were 91·3 (14·1) and 11·7 (1·1) μmol/L for S- and MB-COMT, respectively ( n=6).

Conclusion

The established assay method used to assess S- and MB-COMT activities in human erythrocytes could be useful to elucidate catecholamine metabolism in the normal physiological state as well as in the pathology of certain diseases.
Determination of D-Amino Acid Oxidase Activity in Tumour Cells
Authors: Sasamura Taizo , Matsuda Akihiko , Kokuba Yukifumi
Published: February 2014

Background

We evaluated the assay for determining D-amino acid oxidase (DAAO) activity in tumour cells, rat liver and rat kidney for studying the effects of D-amino acid-containing solution on cancer patients.

Methods and Results

In this method the amount of ammonia produced by the DAAO activity after removal of endogenous ammonia using a Sephadex G25 column was determined. The highest activity was observed in rat kidney, which was almost eight times that found in rat liver. As compared with host tissues, the DAAO activity in tumour cells was considerably less.

Conclusions

This DAAO assay may be useful for analysis of various tissue samples as well as tumour cells.
Creatinine Assays: Time for Action?
Authors: Lawson Nigel , Lang Tim , Broughton Arthur , Prinsloo Peter , Turner Charles , Marenah Christine
Published: February 2014

Background

Major differences in creatinine results between different laboratories and apparent inaccuracies when using commercial lyophilized standards were noted. In order to assess the variation and accuracy of the different methods we conducted a local audit.

Methods

To establish the variation between methods, plasma creatinine was measured on 47 human plasma samples by nine different laboratories using four different methods (Roche, Ortho, Olympus, modified Olympus). To establish the accuracy of the different methods, plasma creatinine was also determined on 16 of the plasma samples by tandem mass spectrometry (MS). In addition, all the laboratories measured the creatinine concentration on a commercial authenticated sample.

Results

All four methods gave significantly different ( P< 0·0001) plasma creatinine results when compared with each other. Generally, creatinine results produced by the Ortho method were considerably higher than those of the other methods, especially at higher creatinine concentrations (differences across methods between the lowest and highest result for the same sample ranged between 8% and 33%). All four methods generally gave higher results than those determined by tandem MS for samples with creatinine concentrations of < 250 μmol/L. Above this concentration the Olympus and Roche methods produced creatinine results that were lower then the tandem MS results, whereas results from the Ortho method were higher. Major matrix problems were found when a commercial lyophilized standard was used for creatinine estimation.

Conclusion

No method gave good agreement with the tandem MS results, and there were major differences in measured plasma creatinine concentrations (up to 30% difference) between the various methods. We suggest that efforts should be made to standardize plasma creatinine measurement across all laboratories to minimize these problems.
Detection of Myelin Basic Protein in Cerebrospinal Fluid and Serum from Patients with HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis
Authors: Ohta Mitsuhiro , Ohta Kiyoe , Nishimura Masataka , Saida Takahiko
Published: February 2014

Background

Human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) is a chronic inflammatory disease that primarily affects the spinal cord and may be a neurological syndrome that is clinically similar to multiple sclerosis (MS). Myelin basic protein (MBP) in the cerebrospinal fluid (CSF) of MS patients is generally measured by radio-immunoassay. We have recently established a sensitive enzyme-linked immunosorbent assay (ELISA) and measured the MBP concentrations in CSF and serum of HAM/TSP patients.

Methods

A sensitive two-site ELISA capable of measuring MBP at a concentration as low as 30pg/mL in serum and CSF samples was used.

Results

Significantly higher CSF MBP concentrations were detected in 61% of HAM/TSP patients than in patients with non-neurological diseases. Serum MBP concentrations were also higher in 9% of HAM/TSP patients compared with patients with non-neurological diseases or healthy controls.

Conclusions

Using our ELISA system, we detected MBP in CSF and serum not only in patients with central active demyelination as in MS, but also in patients with spinal cord demyelination as in HAM/TSP
Serum Sialic Acid, a Possible Cardiovascular Risk Factor is Not Increased in Fijian Melanesians with Impaired Glucose Tolerance or Impaired Fasting Glucose
Authors: Crook MA , Goldsmith L , Ameerally P , Lumb P , Singh N , Miell J , Russell-Jones D
Published: February 2014

Background

Serum total sialic acid (TSA) has been shown to be a strong cardiovascular risk factor with increased concentrations being associated with increased mortality. Serum TSA is also elevated in patients with type 2 diabetes including those with micro- and macrovascular complications. We wished, therefore, to test the hypothesis that serum TSA may be abnormal in individuals with impaired glucose tolerance (IGT) and impaired fasting glucose (IFG), in Fijian Melanesians.

Method

Twenty-one subjects with IGT (17 women and four men) were recruited along with 20 subjects with IFG (14 women and six men) and 22 normal subjects (12 women and 10 men). Serum TSA was 2·18 ± 0·027 mmol/L, 2·19 ±0·033mmol/L and 2·24 ±0·042 mmol/L in the three groups, respectively, which was not statistically different. Both systolic and diastolic blood pressure were, however, higher in the IGT group compared with the IFG and normal groups ( P< 0·04).

Conclusion

Serum TSA is not elevated in Fijian Melanesians with IGT and IFG although it is reported to be elevated in type 2 diabetes mellitus in other populations. Further research is needed to establish why serum TSA is a potent independent cardiovascular risk factor and is elevated in type 2 diabetes mellitus in some populations.
Ethnic Differences in Total and HDL Cholesterol Concentrations: Caucasians Compared with Predominantly Punjabi Sikh Indo-Asians
Authors: Gama R , Elfatih AB , Anderson NR
Published: February 2014

Background

In comparison with Caucasians, Indo-Asians resident in the UK have similar total cholesterol but lower HDL cholesterol (HDLC) concentrations. It is however possible that cardiovascular risk factors may vary between culturally different Indo-Asians.

Methods

We present data on 223 Indo-Asians (129 men, 94 women) and 787 Caucasians (421 men, 366 women) in whom a laboratory-based coronary heart disease (CHD) risk score calculation had been requested.

Results

Total cholesterol concentrations were similar in Indo-Asians and Caucasians. HDLC concentrations were higher ( P< 0·001) in Caucasians [1·4 (1·3–1·4) mmol/L; median (95% confidence intervals)] than in Indo-Asians [1·2 (1·2–1·3) mmol/L]. Indo-Asian women [1·2 (1·2–1·3) mmol/L], Indo-Asian men [1·2 (1·2–1·3) mmol/L] and Caucasian men [1·2 (1·2–1·3) mmol/L] had similar HDLC concentrations but these were all lower ( P< 0·001) than those in Caucasian women [1·4 (1·3–1·4) mmol/L].

Conclusion

We confirm low HDLC concentrations in Indo-Asians, but propose that this is solely due to low HDLC concentrations in Indo-Asian women. Since Indo-Asians in Wolverhampton are predominantly Punjabi Sikhs, we suggest that the difference between this study and previous reports may be due to heterogeneity of CHD risk factors within culturally diverse Indo-Asians.
Arterial Blood Gas Analysis: Selecting the Clinically Appropriate Option for Calculating Base Excess
Authors: Peake Michael J , White Graham H
Published: February 2014

As part of arterial blood gas analysis, base excess is often reported as a measure of non-respiratory acid-base disturbance. Most blood gas analysers offer the option of calculating either the base excess of the blood sample or the base excess of the extracellular fluid (ECF). We report a case that illustrates that selecting the physiologically appropriate parameter avoids the potential for misinterpretation of acid-base data. We recommend that the base excess of the ECF is the appropriate metabolic blood gas parameter for clinical use.
Statistical validation of reagent lot change in the clinical chemistry laboratory can confer insights on good clinical laboratory practice
Authors: Cho Min-Chul , Kim So Young , Jeong Tae-Dong , Lee Woochang , Chun Sail , Min Won-Ki
Published: February 2014

Verification of new lot reagent’s suitability is necessary to ensure that results for patients’ samples are consistent before and after reagent lot changes. A typical procedure is to measure results of some patients’ samples along with quality control (QC) materials. In this study, the results of patients’ samples and QC materials in reagent lot changes were analysed. In addition, the opinion regarding QC target range adjustment along with reagent lot changes was proposed. Patients’ sample and QC material results of 360 reagent lot change events involving 61 analytes and eight instrument platforms were analysed. The between-lot differences for the patients’ samples (ΔP) and the QC materials (ΔQC) were tested by Mann–Whitney U tests. The size of the between-lot differences in the QC data was calculated as multiples of standard deviation (SD). The ΔP and ΔQC values only differed significantly in 7.8% of the reagent lot change events. This frequency was not affected by the assay principle or the QC material source. One SD was proposed for the cutoff for maintaining pre-existing target range after reagent lot change. While non-commutable QC material results were infrequent in the present study, our data confirmed that QC materials have limited usefulness when assessing new reagent lots. Also a 1 SD standard for establishing a new QC target range after reagent lot change event was proposed.
Optimal Assay of LDH and α-HBD at 37 °C
Authors: McQueen M. J.
Published: February 2014

The optimal substrate, hydrogen ion, and coenzyme concentrations for Lactate Dehydrogenase and Alpha-Hydroxybutyrate Dehydrogenase have been established at the physiological temperature 37°C, using an LKB 8600 Reaction Rate Analyzer.
The Indocyanine Green Extraction Test of Liver Function in Pulmonary Disease
Authors: Edwards M. , Saunders R. A. , Thomas A. J.
Published: February 2014

Indocyanine green extraction and galactose tolerance have been measured in 6 normal subjects and 27 patients with marked reduction of ventilatory capacity. In 21 of the 27 patients the indocyanine green extraction was definitely abnormal, the other six gave borderline results. The galactose tolerance test was abnormal in 19 of 27 cases with a correlation coefficient of 0.69.

The work indicates that a high proportion of patients with obstructive airway disease have evidence of liver dysfunction when conventional liver function tests are normal. It is postulated that this is due to reduced hepatic blood flow and hepatic congestion.
Serum Bile Acids in Cholestatic Liver Disease: Their Measurement and Significance
Authors: Murphy G. M.
Published: February 2014

A relatively rapid and specific method for the estimation of serum individual bile acids, conjugated and free, in small volumes (1 ml) of sera from patients with liver disease has been developed. This method has been applied to a study of 25 patients with liver disease. Cholestatic liver disease has been found to be associated with an increase in serum monohydroxy bile acids which appear to be of an unsaturated nature. No association was found between the concentration of any particular bile acid and the presence or absence of pruritus.
Bacterial Inhibition Assays for Phenylketonuria and other Metabolic Disorders
Authors: Lindsay G.
Published: February 2014

Experience with the Guthrie test in Scotland is reviewed. The test continues to be inexpensive and reliable for the detection of PKU in neonates. It is possible to use the specimen obtained for the test to screen for a variety of additional disorders with minimal addition of cost and effort.
A Large Scale Comparison of the Bacteriological Inhibition Assay and the Automated Fluorimetric Method for Phenylketonuria Screening
Authors: Holton J. B.
Published: February 2014

Phenylketonuria screening by blood phenylalanine assay has been carried out on 41 821 newborn infants using the bacteriological inhibition assay method and 22 365 of the samples were tested also by an automated fluorimetric technique. The methods were equally effective in detecting infants with phenylketonuria and false positives can be kept to small numbers in both cases without risk of missing true positive results. A large proportion of infants having borderline results, particularly with the fluorimetric method were shown to have transient tyrosinaemia. Since the cost of the fluorimetric method compared favourably with the bacteriological assay and it has some practical advantages, it should be considered seriously for phenylketonuria mass screening.
Screening the Newborn Population of Wales by the Woolf Technique
Authors: Bradley D. M.
Published: February 2014

The Woolf technique for screening for inborn errors of metabolism by urine chromatography and spot tests has been applied to the screening of all infants born in Wales (approximately 47 000 per annum). With the method as used at the present time, the same sample can reveal, not only phenylketonuria, but also six other abnormal urinary constituents. The method causes no disturbance to the baby and almost total coverage of the population (above 98%) has been achieved.
A Thin Layer Chromatographic Method for Use in Neonatal Screening to Detect Excess Amino Acidaemia
Authors: Ireland J. T. , Read Ruth A.
Published: February 2014

A thin-layer chromatographic treatment of blood samples obtained for Guthrie testing is described and preliminary results reported.
Nitrogen Balance in the Post-Operative Patient Receiving Parenteral Nutrition
Authors: Ames A. C. , Thomas A.
Published: February 2014

Nitrogen balance was measured in patients receiving balanced parenteral nutrition, most of whom were recovering from major surgery involving the alimentary tract. Their pre-operative nutritional status was found to be an important factor in relation to the nitrogen balance that was induced. Positive nitrogen balance did not occur in patients with little or no pre-operative weight loss, but when the weight loss was more than 6 kg. positive or very small negative nitrogen balances were readily induced. The urine creatine/creatinine ratio which is an indirect index of muscle metabolic activity can be used to anticipate the nitrogen balance that may be achieved in a post-operative patient receiving parenteral nutrition.
Automation of the Clinical Laboratories with a D.N.A. Computer System
Authors: Côté R. A.
Published: February 2014

The clinical laboratories of the University Hospital at Sherbrooke have been computerised with a small dedicated system. The D.N.A. System is described generally and then more specifically as installed at Sherbrooke and is critically evaluated after one year of operation.
The Application of the Vickers M-300 High Speed Multichannel Analyser to Clinical Chemistry—Preliminary Report
Authors: Bick M. , Lindridge J. M. , Mitchell F. L. , Pickup J. F. , Rideout J. M. , Snook M.
Published: February 2014

The development and evaluation of the Vickers M-300 is discussed together with problems connected with its introduction into routine use. It possesses versatility, high capacity and precision.
On a Standard Temperature for Clinical Enzymology
Authors: King J.
Published: February 2014

The need for a standard temperature for clinical enzyme assays is discussed. The inadequacy of temperature correction factors is demonstrated and from this it is inferred that reaction and standard temperature must be the same. The advantages and disadvantages of various temperatures are examined and it is concluded that 37°C is the most practical of the alternatives.
The Effect of the Patient's Acid-Base Balance on Azostix Strips' Estimation of Blood Urea
Authors: Hall S. M. , Preston I. W.
Published: February 2014

Severe disturbance of the patient's acid-base balance may cause interference with the Azostix test for blood urea. The strips gave underestimates in blood specimens from some of the severely acidotic patients tested, and slight overestimates in a few of the severely alkalotic ones.
Simplified Area Measurement in Two-Dimensional Immunoelectrophoresis
Authors: Versey J. M. B. , Slater L.
Published: February 2014

A simplified method of measuring two-dimensional immunoelectrophoresis slides is described. The correlation between measurements made by the simplified method and by a graphic digitiser is very good. It is suggested that this simpler, more rapid, and cheaper method of measurement may increase the clinical potential of the technique.
Determination of Phospholipid Fractions in Red Blood Cells in Retarded Physically Handicapped Children
Authors: John Fay M. , Forrest G. C.
Published: February 2014

Phospholipids from the red cells of 85 children, both normal and belonging to various clinical groups, have been extracted and subjected to silica gel chromatography. The several phospholipids have been quantitated. The results have not proved to be useful in diagnosis and hence do not confirm earlier reports. The problems associated with analysis of phospholipids by this type of method are discussed.
Rapid, Standardised Blood Barbiturate Determination
Authors: Jamieson A. , Frew M. W.
Published: February 2014

A modification of Broughton's method for the determination of barbiturate in biological fluids is described which reduces the time of analysis to 15 min. and requires only 2 ml blood. Minimal reagents and apparatus are required. The method has been standardised and is accurate to barbiturate concentrations as low as 0.5 mg/100 ml blood.
Assessment of a Simple Technique for the Determination of Serum Thyroxine
Authors: Badman H. G. , Platten Angela F.
Published: February 2014

The diagnostic accuracy and precision of the Thyopac-4 Kit for measuring serum thyroxine is described. A simple work-saving modification to the procedure is suggested and a normal range established. The test is satisfactory for the diagnosis of hypo-and hyperthyroidism, correlating well with clinical assessments and the measurement of T3 uptake. The precision of the technique is considerably better than that for P.B.I. and there are no time or temperature dependent stages. It can be scaled down for paediatric use.
A Report on the Regional Quality Control of Serum Alkaline Phosphatase
Authors: Teasdale P. R.
Published: February 2014

A scheme for the Regional Quality Control of serum alkaline phosphatase determination is described. the results are presented and interpreted. Recommendations are made for the calibration of routine methods. It is suggested that this scheme may provide a basis for the future study of other enzyme determinations.
Measurement of Total, Ultrafilterable and Ionised Serum Calcium
Authors: Rushton M. L. , Sammons H. G. , Gosling P. , Robinson B. H. B.
Published: February 2014

The development and assessment of methods for measurement of total, ultrafilterable and ionised serum calcium is given. An existing fluorimetric technique for total calcium has been automated and modified for routine use. A device for rapidly preparing serum ultrafiltrates has been developed and an electrometric method for ionised calcium measurement assessed. Values in normal subjects are given for all three fractions and compared with the findings of other workers.
Ames Award Lecture 1972. An Investigation of the Determination of Serum Cholesterol by an Enzymatic Method
Authors: Flegg Heather M.
Published: February 2014

The enzymatic determination of total serum cholesterol is described. The source of the enzyme cholesterol dehydrogenase is the bacterium Nocardia erythropolis. A comparison is made between the enzymatic assay and an automated Liebermann-Burchard serum cholesterol determination.
Simple Flame Spectrophotometric Assay of Serum Lithium
Authors: Woollen J. W. , Wells M. G.
Published: February 2014

A method is described for the flame spectrophotometric determination of lithium in serum using a simple 1/50 dilution in water. By using an instrument having a diffraction grating monochromator, non-specific emission (due to protein) is eliminated.
An Inter-Laboratory Comparison of Several Commercial Sera on the SMA 12/60
Authors: Nisbet J. , Jarvis A.
Published: February 2014

Several commercial sera were analysed on the SMA 12/60 in 12 laboratories. The results were compared with the manufacturers' target values and the precision and accuracy on each channel discussed.
Automated Two-Dimensional Immunoelectrophoresis and its Application to the Analysis of C3 and C4 in Rheumatoid Arthritis and Systemic Lupus Erythematosus (S.L.E.)
Authors: Versey J. M. B.
Published: February 2014

A semi-automated two-dimensional immunoelectrophoretic method has been developed which is quicker and cheaper to use than the original system, making it more suitable for routine use. It is accurate and reproducible and is suitable for complement conversion studies where C3 and C4 conversion can be measured with 5 and 10% reproducibility respectively. Conversion of C3 and C4, observed in both S.L.E. and rheumatoid arthritis, is an early and sensitive index of disease activity. Total C3 levels, although fluctuating widely in the course of the disease, were not shown to be as sensitive an index.
Routine Clinical Measurements of Transferrin in Human Serum
Authors: Dixon K.
Published: February 2014

Data from the Wellcome Group Quality Control Programme and from the National Quality Control Scheme were kindly provided by Dr. B. A. L. Hurn and Prof. T. P. Whitehead respectively. Figures 1 and 2 are reproduced, with permission, from the Journal of Biological Chemistry and Clinica Chimica Acta respectively.
A Simplified Method for the Estimation of Lecithin in Amniotic Fluid
Authors: Hodge J. S.
Published: February 2014

A simplified method for the determination of lecithin in amniotic fluid by thin-layer chromatography is described. The results are similar to those found in previous reports and are suitable for the clinical prediction of foetal lung maturity. Factors which may influence the interpretation of the results are discussed.
Prognosis in Paracetamol Self-Poisoning: The Use of Plasma Paracetamol Concentration in a Region without a Poisoning Treatment Centre
Authors: Stewart M. J. , Simpson E.
Published: February 2014

Published criteria for prognosis following self-poisoning with paracetamol have been applied to 30 cases in a region without centralised facilities for investigation of the poisoned patient. The results show that, despite difficulties in collection and transport of specimens, useful prognostic indices can be provided by a central laboratory. The biochemical assessment of liver damage is discussed and one of two fatal cases is presented in detail.
Serum 5′ Nucleotidase and Alkaline Phosphatase Isoenzymes in Diagnosis, with Special Reference to Haemochromatosis
Authors: Parsons Valerie , Walker R. J. , Howorth P. J. N.
Published: February 2014

Serum 5′ nucleotidase (NTP) was determined on 91 sera by nickel inhibition and beta-glycerophosphate substrate competition; the latter method was found to be preferable. The isoenzyme pattern of serum alkaline phosphatase (ALP) in the same 91 sera was studied by polyacrylamide gel electrophoresis and was found more helpful in patient management than serum NTP.

The serum ALP isoenzyme pattern was further studied in 50 patients with haemochromatosis. Nine out of 10 patients with clinical or radiological joint disease had a raised serum total ALP caused in half by the hepatic isoenzyme and half by the bone isoenzyme, without any clear-cut pattern. Four out of five patients with hepatoma had a raised serum total ALP due to the hepatic isoenzyme. The persistence of a high serum ALP in a patient treated actively for haemochromatosis may indicate malignant change in the liver.
Accuracy and Standardisation of Serum Thyroxine Assays
Authors: Watson D. , Lees S. , Stafford J. E. H.
Published: February 2014

Serum thyroxine was assayed concurrently by at least two of three different radio-displacement analysis kits—‘Tetralute’ (Ames), ‘Tetrasorb’ (Abbott) and ‘Thyopac-4’ (Radiochemical Centre). Repeated and careful cross checking by each of the methods was carried out on the ‘standard’ sera supplied with the kits and on other commercially available control sera. Differences of −3 to + 32% in apparent T-4 concentration were found. An unacceptable variability in T-4 content amongst batches of the same control sera was also evident which can be explained only by a lack of constancy in the commercial serum T-4 ‘standards’.

The molar extinction coefficients, water and tri-iodothyronine contents of commercial ‘pure’ thyroxine preparations indicate purities of 89–99 %. An examination of published ‘euthyroid’ ranges and those found by the ‘kit’ radiometric methods suggests that many normal serum T-4 values are based on the use of an impure primary or doubtful secondary standard. A primary standardisation of the assay with thyroxine of known purity and of known concentration, as determined from its molar extinction at 324 nm is advocated. Using this procedure, the normal euthyroid range for serum T-4 is 55–148 nmol T4/1 (2.8–7.5 μg T-4I/100 ml) or close to it—in agreement with the earlier findings of Howarth and Maclagan (1969) and Ekins et al. (1969).

During the period studied, ‘Tetralute’ produced the most accurate results.
Intrauterine Fetal Growth Retardation: A Comparison of Human Placental Lactogen Urinary Oestriol and Biparietal Diameter Measurements
Authors: Robinson H. P. , Chatfield W. R. , Logan R. W. , Hall Frances
Published: February 2014

Forty-two ‘at risk’ pregnancies were serially monitored by sonar biparietal cephalometry, 24 h urinary oestriol assays and determination of serum human placental lactogen. The results were assessed by a scoring system, and it was found that a combination of sonar cephalometry and 24 h urinary oestriol assays gave the most reliable prediction of intrauterine growth retardation.
A Method of Assessing Amniotic Fluid Lecithin Concentrations and Predicting Foetal Lung Maturity, by Estimating Total Palmitic Acid Concentration Using G.L.C.
Authors: Warren Christine , Holton J. B. , Allen J. T.
Published: February 2014

A rapid G.L.C. method for estimating total palmitic acid in amniotic fluid is described and it is shown that the principal source of this substance is lecithin. Thus, the technique is a convenient means of assessing amniotic fluid lecithin concentrations and of predicting the maturity of the foetal lung.
A New Haemoglobin Variant Haemoglobin J Birmingham a 120 (H3) Ala → Glu
Authors: Kamuzora H. , Lehmann H. , Griffiths K. D. , Mann Jillian R. , Raine D. N.
Published: February 2014

An abnormal haemoglobin, which on paper electrophoresis has the mobility of Hb J, has been found in two brothers and, in the heterozygous state at least, is not associated with serious clinical abnormality. The structure of this hitherto unreported haemoglobin is α 120 (H3) Ala → Glu and it is named Haemoglobin J Birmingham.
Adaptation of the Analmatic for Use in Determination of Serum Thyroxine
Authors: Hood W.
Published: February 2014

P.B.I. determinations are now being replaced in many laboratories by thyroxine determinations, but the latter have previously had the disadvantage of not being automated. The Analmatic preparation unit has been adapted for the large scale determinations of serum thyroxine using the Radiochemical Centre's Thyopac-4 kits. There is satisfactory correlation between the manual and automated techniques. Both the between-batch and within-batch precision were found to be better than that for the manual method.