William Graham Wood

Instand e.V. · External Quality Assessment

External quality assessment is a standard procedure for many medical laboratories, especially those accredited according to ISO 15189. INSTAND has developed web-based quality control surveys (WQ) with integrated case-based learning in collaboration with the Institute for Teaching and Educational Research in Health Sciences (IDBG), University of Wit...

Urinary sediment components are mainly unstable, especially in their original forms. This makes the use of such material in routine external quality assessment surveys (EQAS) almost impossible. The development of an alternative EQAS for urinary sediment using photomicrographs (visual-sample EQAS) is described here, together with results, improvemen...

This article deals with “matrix effects” in immunoassay systems. As each component has its own matrix (buffer, antibody, separation agents), the term matrix effect - usually only referring to the matrix of the sample - has been replaced by the term interference effect. The possible sites of interference have been dealt with in turn, taking each com...

The aim of this report is to examine what--if any--effects the introduction of the European Directive 98/79/EC has had on the performance of in-vitro diagnostic devices (kits) used in determining hormones and related measurands in medical diagnostic laboratories. The observations covered the period from 1993-2008, results being taken from EQA surve...

This article mainly describes the effects of boric acid and borates often used as bacteriostatic agents in urine collection for microbiological examination, on the results obtained in the measurement of uric acid in urine using the uricase [EC.1.7.3.3] method. The bias in results is not unidirectional, the spread of results being much larger than i...

The article describes the development and evaluation of the alkaline haematin detergent (AHD575) method for the determination of haemoglobin in blood without the need for toxic materials and suitable for use in laboratories in countries with limited resources and restricted import of toxic materials. The validation of the method has been performed...

This article has been designed to give a brief overview of antigen-antibody reactions, especially in the form used in immunoassays. The different types of label and assay design have been described briefly. The report has not been designed as a brief text book, so that diagrams referring to assay principles have been omitted. The number of tables a...

This article reports on the performance of two "dry" chemistry devices, (Reflotron, Roche Diagnostics and Vitros, Johnson & Johnson) and compared them with classical "wet" chemistry analysers in four commercially produced quality assessment samples (Roche PNU and PPU and Seronorm Human and Human High Controls) sent repeatedly over a 12-month observ...

Point of care testing (POCT) is evolving at an ever increasing rate. This article deals mainly with the aspect of POCT for blood glucose and the problems of external quality assessment (EQA) of point of care devices (POCD). At the present time it is only possible to control precision with EQA, independent of the matrix of the test materials (synthe...

This report was written in response to the article by Wood published recently in this journal. It describes a practical solution to the problems of controlling the pre-analytical phase in the clinical diagnostic laboratory. As an indicator of quality in the pre-analytical phase of sample processing, a target analyte was chosen which is sensitive to...

External quality assessment surveys for thyroid-related antibodies have been offered by INSTAND for 20 years. During this time, some problems have remained, especially those between the similarity of samples sent and routine patient samples. Here the questions of "matrix effects" and "commutability of results" are topics discussed at most EQA-meeti...

In this study a new principle of measurement in LC-MS/MS (liquid chromatography mass spectrometry) for determination of the immunosuppressive drugs sirolimus, everolimus, tacrolimus, and cyclosporin A has been introduced by using the Cs+ ion as the product ion in the multiple reaction monitoring mode (MRM). Separation of the immunosuppressive agent...

This short article describes the results obtained in both internal and external quality assessment of point of care devices (POCD) for the monitoring of blood glucose. The results show that the use of synthetic, serum and whole blood matrices for the samples do not markedly change the inaccuracy of measurement. It is only possible to check precisio...

This article describes an essential improvement of the published candidate reference measurement procedure for digoxin and digitoxin and compares it with the original method. The novelty of the method lies in the measurement of the caesium (Cs+) ion as product ion in the multiple reaction monitoring mode (MRM) with potentially improved analytical s...

This review shows the current analytical quality for the following analytes used as tumour markers in the external quality assessment (EQA)-programmes of Instand e.V., a national EQA-organiser in Germany: Corticotropin (ACTH), growth hormone (GH, hGH), prolactin (PRL), chorionic gonadotropin (CG, hCG), calcitonin (CT, hCT), thyroglobulin (Tg), carc...

This article describes practical problems in carrying out witness audits in terms of the international normal ISO 15189, with special regard to the situation in medical diagnostic laboratories in Germany. The presence of central laboratories--for example in hospitals--and decentralised laboratories--usually in the private sector--present different...

The present article presents a critical review of the current guidelines of the Federal Medical Council (Richtlinie der Bundesärztekammer--[RiliBAK]) in Germany, both for internal and external quality control. Examples have been chosen for analytes which present problems. These include thyrotropin (TSH) and human chorionic gonadotropin (hCG). Data...

The change from measuring enzyme catalytic activity concentrations from 25 degrees C to 37 degrees C in the German Federal Republic has led to the need for new reference ranges for defined patient groups and for healthy individuals. Up to now, these are only present as tentative values and are incomplete, especially for children. This article descr...

Six thyroid analytes (free and total triiodothyronine and thyroxine, thyrotropin and thyroglobulin) have been followed up over a 10 year period in a national external quality assessment scheme (EQAS) organised by the Institute for Standardisation and Documentation in the Medical Laboratory (INSTAND). I. The following points were observed: II. The i...

Four thyroid antibodies (antibodies to microsomes [MAb], thyroid peroxidase [anti-TPO], thyroglobulin [anti-Tg] and TSH-receptor [TRAB, THYBIA]) have been followed up over a 10-year period in a national external quality assessment scheme (EQAS) organised by the Institute for Standardisation and Documentation in the Medical Laboratory (INSTAND e.V.)...

This article describes the preparation and internal and external evaluation of materials, critical issues in the external quality assessment (EQA) of point-of-care testing (POCT) devices for measuring blood glucose. A comparison was made between different materials, both of natural and synthetic origin and with and without stabilisers. The aims wer...

This article describes a method of high analytical sensitivity, reproducibility and trueness for the determination of digoxin and digitoxin in serum or plasma at therapeutic levels using a combination of high-pressure liquid chromatography (HPLC), isotope-dilution mass spectrometry (IDMS) and caesium-adduct formation. A method for threefold deuteri...

This article describes the process of "repairing" a method which has gone out of control, using the gas-chromatographic isotope-dilution mass spectrometric (GC-IDMS) determination of total glycerides in serum, measured as glycerol. The original method used 13C2-glycerol as aqueous internal standard and 12C-tripalmitin dissolved in toluene as extern...

A method is described which uses a combination of gas chromatography and isotope dilution-mass spectrometry (GC-IDMS) to determine the concentration of theophylline (1,3-dimethyl xanthine) in human plasma or serum samples. The effects of similar substituted xanthines - namely theobromine (3,7-dimethyl xanthine), paraxanthine (1,7-dimethyl xanthine)...

The aim of this study was to develop and compare high-performance liquid chromatography (HPLC) and gas chromatography coupled with isotope dilution-mass spectrometry (GC-IDMS) methods with a common extraction procedure for the determination of substituted xanthines in biological matrices such as serum and urine. For HPLC both isocratic and gradient...

The aim of the study was to develop a method for the determination of haemoglobin in plasma suitable for use to set target values for external quality assessment schemes for this analyte using commercially available test kits and equipment. In the early phase of the method development it became clear that the use of a single method, namely HPLC, wo...

The aims of the population-based, cross-sectional survey "Study of Health in Pomerania" (SHIP) are to describe prevalences and distributions of a broad range of diseases, as well as environmental and behavioural risk factors in the region of Pomerania (North-eastern Germany). The examinations are performed in two study units by different physicians...

The adsorption of a number of lipoproteins, i.e., low-density lipoprotein (LDL), oxidized LDL (oxLDL), high-density lipoprotein (HDL), and lipoprotein (a), at silica and methylated silica as well as at the latter surface modified through adsorption of proteoheparan sulfate, was investigated with in situ ellipsometry at close to physiological condit...

A sensitive immunoluminometric assay originally designed to measure C-reactive protein (CRP) in neonates and minimal serum volumes was adapted to measure this protein in a routine method without prior sample dilution. The concentration range covered without prior dilution was 10 micrograms/l to 20 mg/l using a sample volume of 5 microliters serum a...

Severe ovarian hyperstimulation syndrome (OHSS) leads to changes in laboratory analyte concentrations. Whereas elevated aminotransferase activity is often observed, a cholestatic course with hyperbilirubinaemia and icterus seldom occurs. In this report, the case of a 33 year old patient with polycystic ovary syndrome (PCOS) is described who, after...

Data from 7045 subjects were examined. The main groups consisted of the following in- and outpatients: 1414 neonates, 2554 children and adolescents (1336 males, 1218 females), 1209 women directly postpartum, 786 non-pregnant women and 1090 men aged between 18 and 100 years of age. Unless otherwise stated, persons were under medical observation or t...

The Abbott Ultrasensitive II hTSH assay was evaluated in three European centres and its performance compared with its predecessor and with commercially available kits. A total of 408 individuals was included in the study (140 euthyroid, 116 hyperthyroid and 86 hypothyroid subjects, as well as 26 patients with non-thyroidal illness and 30 patients w...

In a study designed to measure lipoprotein(a), cholesterol, cholesterol fractions and triacylglycerols in serum 4004 hospitalised individuals aged between 18 and 100 years were examined. Lipoprotein(a) was determined in 1313 patients (438 males, 875 females) aged 18-59 years and 489 patients (234 males, 255 females) aged 60-100 years. Cholesterol,...

This study was carried out on 625 newborns delivered between July 1993 and December 1994 and 221 children visiting the clinic in the first year of life using an immunoluminometric assay specific for apolipoprotein(a), but calibrated with lipoprotein(a), hence the use of the term (apo)lipoprotein(a) for neonatal values. (Apo)lipoprotein(a) concentra...

The ELITE glucometer (Bayer Diagnostics), which uses a glucose oxidase sensor coupled to an amperometric measurement, was compared with the routine hexokinase method on the EPOS (Eppendorf--Netheler-Hinz) using commercially available reagents (Boehringer-Mannheim). Both methods were carried out using whole blood as sample. The comparison was made u...

Oral iodized oil is the major alternative to iodized salt for correcting endemic iodine deficiency. This study responds to a need for better guidelines in its use. Schoolchildren, aged 6-11 yr, from a severely iodine-deficient area of Algeria received iodized poppy seed oil (Lipiodol) in a single oral dose containing 120, 240, 480, or 960 mg iodine...

Investigations have been made upon the distribution of lipoprotein(a) concentrations in cord and capillary blood from newborns and in serum from in-patient children and adults. Full-term neonates (n = 123), children aged 1 month to 16 years (n = 331) and adults aged between 17 and 88 years (n = 252) of age were included in the study. Lipoprotein(a)...

C-reactive protein and elastase-alpha 1-proteinase inhibitor complexes were compared in the diagnosis of neonatal sepsis and bacterial infections in adults on the intensive care unit. Both analytes were measured in the same sample immediately after receipt. EDTA-plasma samples (n = 115) from 28 neonates (gestational age 29-42 weeks) within the firs...

C-reactive protein and elastase-alpha 1-proteinase inhibitor complexes were compared in the diagnosis of neonatal sepsis and bacterial infections in adults on the intensive care unit. Both analytes were measured in the same sample immediately after receipt. EDTA-plasma samples (n = 115) from 28 neonates (gestational age 29-42 weeks) within the firs...

This study reports the changes in total cholesterol, triacylglycerols, apolipoproteins A-I, B, C-II and (a) before, directly after and 48 hours after chronic renal dialysis on 46 non-selected patients (20 male, 26 female; time since first dialysis 1-203 months (median 22 months), median age 52 years, range 25-82 years). Thirty six of the 46 patient...

Immunoluminometric assays were developed for apolipoproteins A-I, B, C-II (as the apolipoprotein C-II: apolipoprotein B complex), apolipoprotein(a) and lipoprotein(a). The assays were evaluated clinically and methodologically. The results for apolipoprotein A-I, apolipoprotein B and lipoprotein(a) were compared with those obtained by turbidimetric...

Immunometric assays were developed for thyrotropin and thyroglobulin using time-resolved fluorescence as the measurement signal. The assays were suitable for measurements in serum/plasma or in dry blood spots (3 mm diameter). Both assays have acceptable coefficients of variation for dry blood spots (intra-assay median CV < 10%, interassay CV < 15%)...

In order to clarify the mode of inactivation of alpha1-proteinase inhibitor (alpha 1-PI) in pneumonia, 21 immunocompetent patients and 19 immunocompromised patients with acute pneumonia (Groups I and II) were studied. Nine patients successfully treated for pneumonia and 10 healthy volunteers served as controls (Groups III and IV, respectively). The...

The value of measuring the urinary concentration of alpha 2-macroglobulin in addition to that of C-reactive protein (CRP) was assessed in a prospective study of 78 consecutive patients (29 women, 49 men; mean age 48.7 [19-75] years) after renal transplantation. alpha 2-Macroglobulin was never demonstrated in urine when the course was normal (n = 38...

In einer prospektiven Studie wurde bei 78 konsekutiven Patienten (29 Frauen, 49 Männer, mittleres Alter 48,7 [19-75] Jahre) nach Nierentransplantation geprüft, welchen zusätzlichen Wert die Bestimmung der α2-Makroglobulin-Konzentration im Urin neben der des C-reaktiven Proteins besitzt. Bei Normalverläufen (n = 38), Cytomegalievirus-Infektionen (n...

The assay described in this article is based on microtitre plate technology; it employs an europium label. The streptavidin-biotin system has been used and all components are commercially available. The lower detection limit of the assay is below 0.003 mU/l; the standards are made up in newborn calf serum. Correlation with a commercially available...

This article describes the development and clinical evaluation of two-site immunometric assays for ferritin, thyrotropin (TSH), and tumor necrosis factor alpha (TNF(alpha) ) using time resolved fluorescent measurement with streptavidin-europium (STAV-Eu+3) as a label. The liquid phase antibodies were labeled with amidocaproylbiotin-N- hydroxysuccin...

The following analytes were determined with the automated enzyme immunoassay unit, Enzymun-Test System ES 300, and by routine in-house tests, and the results were compared: thyrotropin, free thyroxine, cortisol, immunoglobulin E, digoxin, digitoxin, insulin and carcinoembryonic antigen. The methods used for comparison included two radioimmunoassays...

Serial serum determinations of the tumour associated antigens carcinoembryonic antigen, tissue polypeptide antigen, CA 19-9, CA 15-3 and CA 125 were performed on 70 patients who were undergoing, or had undergone renal transplantation. The period of observation ranged from 4 days pre-operative to 708 days post-operative, although daily monitoring wa...

The interaction between Bacillus Calmette-Guérin (BCG) and the host was investigated after repeated intravesicular BCG-therapy for superficial bladder cancer. Studies were performed on (a) the local reaction in the bladder, (b) the systemic reaction, and (c) short and long term interactions in both the bladder and the serum/plasma. The analytes mea...

A prospective study was undertaken in 73 patients (24 women, 49 men; mean age 47.9 [21-64] years) after renal transplantation to discover whether the presence of C-reactive protein in urine (CRPu) and its serum concentration (CRPs) are of value in the differential diagnosis of abnormal function in the transplanted kidney. CRPu concentration was mea...

Bacterial colonization of the tracheo-bronchial tree is common and an established risk factor for infection in ventilated newborns. Elastase, a highly active proteinase, and lactoferrin, an iron-binding protein and potential modulator of the inflammatory process, are both major constituents of either azurophilic or primary granules of neutrophilic...

Bacterial colonization of the tracheo-bronchial tree is common and an established risk factor for infection in ventilated newborns. Elastase, a highly active proteinase, and lactoferrin, an iron-binding protein and potential modulator of the inflammatory process, are both major constituents of either azurophilic or primary granules of neutrophilic...

Neutrophilic granulocytes in the lower respiratory tract are of decisive importance for the elimination of pathogenic germs in bacterial pneumonia. On the other hand, the liberation of phagocyte products (e.g. elastase) can result in tissue damage in the parenchyma of the lungs. For this reason, we determined in patients suffering from acute pneumo...

The frequency of cytomegalovirus infection was studied in a prospective study of 106 kidney recipients. The detection of cytomegalovirus-immediate-early-antigen and cytomegalovirus-immunoglobulin (IgM) antibodies in serum was used as the reference method and showed that 23.6% (25/106) of all patients were infected. In addition, four urinary protein...

Prostate-specific antigen is found in the prostate in two forms, one with a low (30,000) and one with a high (100,000) relative molecular mass. The latter has recently been found to be a complex of prostate-specific antigen with alpha 1-antichymotrypsin. Immunoluminometric assays were designed for the prostate-specific antigen-alpha 1-antichymotryp...

In einer prospektiven Studie wurde bei 73 Patienten (24 Frauen, 49 Männer, durchschnittliches Alter 47,9 [21–64] Jahre) nach Nierentransplantation geprüft, ob der Nachweis des C-reaktiven Proteins im Urin (CRPu) neben der Bestimmung der Serumkonzentration (CRPs) von Nutzen für die Differentialdiagnose von Transplantatfunktionsstörungen ist. Die CRP...

The frequency of cytomegalovirus infection was studied in a prospective study of 106 kidney recipients. The detection of cytomegalovirus‐immediate‐early‐antigen and cytomegalovirus‐immunoglobulin (IgM) antibodies in serum was used as the reference method and showed that 23.6% (25/106) of all patients were infected. In addition, four urinary protein...

Prostate-specific antigen is found in the prostate in two forms, one with a low (30,000) and one with a high (100,000) relative molecular mass. The latter has recently been found to be a complex of prostate-specific antigen with alpha 1-antichymotrypsin. Immunoluminometric assays were designed for the prostate-specific antigen-alpha 1-antichymotryp...

Results from a multicenter evaluation of two new enzyme-linked immunosorbent assays [Enzymun-Test for follitropin (FSH) and lutropin (LH)] are presented and compared with results from 11 other commercial immunoassays, radioactive as well as nonradioactive. Enzymun-Test FSH and LH assays are suitable for automated systems and manual applications. Th...

The introduction of cyclosporin gave rise to an additional problem in the surveillance of renal transplant patients, namely the differentiation between cyclosporin toxicity and acute transplant rejection. The development of assays for specific proteins in urine has produced a non-invasive solution to this problem. In 55 renal transplant patients th...

In a prospective study the occurrence of cytomegalovirus (CMV) infection was diagnosed by demonstrating CMV-immediate early antigen (IEA) in the blood in 13 out of 68 (19%) patients who had undergone renal transplantation (27 women, 41 men, mean age 46.3 [21-64] years). Twenty-four hour urine samples were collected at the same time for quantitative...

Typical alterations of the white blood cell count are often missed during the acute course of infectious diseases. Activiation and degranulation of granulocytes are followed by elevation of E alpha 1 PI and lactoferrin plasma concentrations under these conditions. The aim of our study was the evaluation of the diagnostic significance of these granu...

This article deals with "matrix effects" in immunoassay systems. As each component has its own matrix (buffer, antibody, separation agents), the term matrix effect--usually only referring to the matrix of the sample--has been replaced by the term interference effect. The possible sites of interference have been dealt with in turn, taking each compo...

The state of the art in practical external quality assessment (EQA) in the Federal Republic of Germany is described. Two organizations, INSTAND (Institute for Standardization and Documentation in Medical Laboratories) and the German Society for Clinical Chemistry (DGKCh) have been appointed by the central government to organize and run EQA schemes....

In einer prospektiven Studie wurde bei 68 nierentransplantierten Patienten (27 Frauen, 41 Männer, durchschnittliches Alter 46,3 [21-64] Jahre) geprüft, ob die Bestimmung der β2-Mikroglobulin-Konzentration im Urin die Diagnose einer Cytomegalievirus(CMV)-Infektion erleichtert. Bei 13 der 68 Patienten (19 %) wurde eine CMV-Infektion durch den Nachwei...

Mortality and long-term neurologic sequelae are still frequent complications of meningitis despite effective antibiotic treatment. This suggests that pathogen-independent inflammatory mechanisms may play an important role in the course of this illness. Neutrophil granulocytes form the primary immune defense in meningitis. Once activated, these cell...

This short communication describes the use of spiroadamantane-1,2 dioxetane substrates for alkaline phosphatase and beta-D-galactosidase in the development of luminescence-enhanced enzyme immunoassays. Until the present work, only peroxidase-luminol/peroxidase systems had been used in such assays. The light reaction kinetics were studied from the t...

This communication presents four different assay systems for the determination of myeloperoxidase in body fluids. One is based on conventional chemiluminescence, two on luminescence-amplified enzyme measurement using either spiroadamantane-1,2-dioxetanes with alkaline phosphatase or luminol/peroxidase/4-iodophenol coupled with a peroxidase label. T...

Long-term replacement with human alpha 1-antitrypsin (60 mg/kg once a week intravenously) was carried out in seven patients with homozygous alpha 1-antitrypsin deficiency (7 males, mean age 50.8 [40-59] years) and progressive pulmonary emphysema for an average of 16 (13-20) weeks. After at least 12 weeks' therapy the concentrations of alpha 1-antit...

A 36 year old male was admitted to the intensive care unit with acute digitalis intoxication after ingestion of 350 digitoxin tablets (=35 mg digitoxin). He was treated with Fab fragments of a digitalis antiserum raised in sheep, the concentrations of digitoxin in serum, urine and dialysates being measured with two automated digitoxin immunoassays...

The following serum analytes were measured in 464 patients with defined carcinomas and other tumours as well as those with chronic obstructive lung disease and under regular haemodialysis, and in 261 healthy controls: thyrotropin (TSH), thyroxine (T4), triiodothyronine (T3), free thyroxine (fT4), thyroxine binding globulin (TBG) and transthyretin (...

This article briefly describes the use of a photon counting system (ARGUS-100) in the detection of low levels of light. The ARGUS-100 was used in determining ATP in cell sections from tumor tissues and in measuring a luminescence-enhanced immunoluminometric assay, using ferritin as the analyte, based on the luminol-peroxide-4-iodophenol reaction wi...

A chemiluminescent assay for hepatitis-B surface antigen is described which used an isoluminol derivative as the label. The assay is precise intra-assay CV, 1.96-2.45%; inter-assay CV, 5.26-8.11% and has a lower detection limit for hepatitis-B surface antigen of 1.3 U/l.

Bei sieben Patienten mit homozygotem α1-Antitrypsin-Mangel (sieben Männer, mittleres Alter 50,8 [40-59] Jahre) und progredientem Lungenemphysem wurde über durchschnittlich 16 (13-20) Wochen eine Dauersubstitution mit humanem α1-Antitrypsin (60 mg/kg pro Woche intravenös) durchgeführt. Nach mindestens zwölf-wöchiger Therapie wurden die Konzentration...

The problems of setting up routine non-radioisotopic immunometric assays for specific urinary proteins were analyzed, and solutions are presented here. The effects of storage (up to 10 days at 4°C and up to 90 days at -37°C) were studied. Reference ranges for healthy volunteers (56 with and 44 without sediment) were established for the following 10...

An immunoluminometric assay for plasma lactoferrin has been developed and used to study the levels in children and neonates with viral and bacterial infections. The reference range for plasma lactoferrin was 50–250 μg/l. Lactoferrin levels were significantly higher in patients with bacterial versus viral infections.

Immunoluminometric assays for lactoferrin and elastase-alpha 1-proteinase inhibitor complexes were developed using solid-phase methodology, which has already been published from this laboratory. The aim of the study was to develop a rapid method to see whether elevated granulocyte activity was present in the lung, as for example in neonatal sepsis....