Calibration - an under-appreciated component in the analytical process of the medical laboratories.

Calibration of an analytical measurement procedure is an important basis for the reliability of patient results. Many publications and as well as procedures on how to estimate quality control and interpret those results have been become available over the years. In this publication we are focusing on the critical part of the calibration as there are no clear communication or guidelines on how to perform it.

Time to address quality control processes applied to antibody testing for infectious diseases.

As testing for infectious diseases moves from manual, biological testing such as complement fixation to high throughput automated autoanalyzer, the methods for controlling these assays have also changed to reflect those used in clinical chemistry. However, there are many differences between infectious disease serology and clinical chemistry testing, and these differences have not been considered when applying traditional quality control methods to serology. Infectious disease serology, which is highly regulated, detects antibodies of varying classes and to multiple and different antigens that change according to the organisms' genotype/serotype and stage of disease.

Collective opinion paper on findings of the 2011 convocation of experts on laboratory quality.

In April of 2011, Bio-Rad Laboratories Quality System Division (Irvine, CA, USA) hosted its third annual convocation of experts on laboratory quality in the city of Salzburg, Austria. As in the past 2 years, over 60 experts from across Europe, Israel, USA and South Africa convened to discuss contemporary issues and topics of importance to the clinical laboratory. This year's conference had EN/ISO 15189 and accreditation as the common thread for most discussions, with topics ranging from how to meet requirements like uncertainty to knowledge gained from those already accredited.

Monitoring quality indicators in laboratory medicine does not automatically result in quality improvement.

Background: Data on quality indicators (QIs) should be collected over time in order to identify and continuously monitor clinical laboratory performance and to improve patient safety by identifying and implementing effective interventions. The aim of the present study was to ascertain whether the utilization of a set of quality indicators over a 3-year period resulted in an improvement in the efficiency and effectiveness of an individual laboratory.

Methods: Over a 3-year time interval (2009-2011), a series of 38 QIs covering all stages of the total testing process (21 in the pre-analytic, nine in the analytic and eight in the post-analytic phase) was monitored.

Analytical interferences and analytical quality.

In today's health care system the prevalence of medical errors is high as stated by the report of the Institute of Medicine. A varying error rate of <10% in clinical medical laboratories has been reported in the literature. Most of these errors occur in the pre-analytical phase.

Evaluation of the VITROS 5,1 FS chemistry system in a large pediatric laboratory.

The VITROS 5,1 FS analytical system was evaluated. The measurement of the serum proteins and HDL cholesterol with the newly developed MicroTip technology was compared with other nephelometric and turbidimetric methods. The within-run imprecision for apolipoprotein A1, apolipoprotein B, complement 3, complement 4, transferrin, immunoglobulin A, immunoglobulin M, immunoglobulin G and HDL cholesterol showed coefficients of variation between 0.

Selective oxidation of benzene to phenol over FeAlPO catalysts using nitrous oxide as oxidant.

A tetrahedrally coordinated iron in framework substituted microporous AlPO-5 catalysts are shown to be active and selective for the hydroxylation of benzene to phenol, using nitrous oxide as the oxidant.

Drug interference in clinical chemistry: recommendation of drugs and their concentrations to be used in drug interference studies.

A group of international experts prepared two lists of drugs with their serum/plasma and urine concentrations, which should be used when evaluating the performance of a new laboratory method. The two lists were verified by running in vitro interference studies in three European laboratories on Hitachi instruments. The study identified the following new interferants: acid phosphatase in serum by ibuprofen and theophylline; non-prostatic acid phosphatase in serum by cefoxitin and doxycycline; creatine kinase MB in serum by doxycycline; total bilirubin in serum (Jendrassik-Grof method) by rifampicin and intralipid; total bilirubin in serum (DPD method) by intralipid; creatinine in serum (Jaffe method) by cefoxitin; fructosamine in serum by levodopa and methyldopa; uric acid in serum by levodopa, methyldopa and tetracycline; carbamazepine in serum by doxycycline, levodopa, methyldopa and metronidazole; digitoxin in serum by rifampicin; phenytoin in serum by doxycycline, ibuprofen, metronidazole and theophylline; theophylline in serum by acetaminophen, cefoxitin, doxycycline, levodopa, phenylbutazone and rifampicin; tobramycin in serum by cefoxitin, doxycycline, levodopa, rifampicin and phenylbutazone; valproic acid in serum by phenylbutazone; C3 in serum by intralipid; C4 in serum by doxycycline; rheumatoid factor in serum by ibuprofen and metronidazole; pancreatic amylase and total amylase in urine by acetylcysteine, ascorbic acid, cefoxitin, gentamicin, levodopa, methyldopa and ofloxacin; magnesium in urine by acetylcysteine, gentamicin and methyldopa; beta2-microglobulin in urine by ascorbic acid; total protein in urine by ascorbic acid, Ca-dobesilate and phenylbutazone.

Analyses with the KODAK-Ektachem. Accuracy control using reference method values and the influence of protein concentration. Part II. Substrates.

The reliability of the determination of the most common substrates with the Ektachem 700 was evaluated. Accuracy control was performed in various ways including the comparison of results with reference method values. The influence of protein concentration was investigated systematically using sera containing varying amounts of protein obtained by ultracentrifugation.

Analyses with the KODAK-Ektachem. Accuracy control using reference method values and the influence of protein concentration. Part I. Electrolytes.

The reliability of electrolyte determinations with the Ektachem 700 was evaluated by various means including the use of reference method values. The influence of protein concentration, which may alter the viscosity and hence the speed of diffusion, was systematically investigated by using samples of varying protein concentration obtained by ultracentrifugation. Calcium.

Haemolysis as an interference factor in clinical chemistry.

Using fully mechanized analytical equipment, interference by haemolysis in the determination of 26 clinical chemical parameters was determined quantitatively by adding haemolysate to serum. Haemoglobin concentrations up to 6.6 g/l caused essentially no interference in the following determinations: albumin (immuno-nephelometric), alpha-amylase, calcium, chloride, cholesterol, cholinesterase, creatinine, iron, glucose, glutamate dehydrogenase, uric acid, urea, sodium, inorganic phosphate, total protein, transferrin and triglycerides.

Comparison of 9 methods for the determination of cholesterol.

Seven enzymatic procedures for the determination of cholesterol in serum were compared with the Liebermann-Burchard- and a gas-chromatographic method. Using a decision matrix all methods could be ranked according to reliability and practicability . With the exception of the cholesterol oxidase-coupled Kageyama principle and the Liebermann-Burchard procedure, all the other methods showed similar reliability.