Search

Manual blood smear review is required when an anomaly detected by the automated hematologic analyzer triggers a flag. Our will through this study is to optimize these flagging thresholds for manual slide review in order to limit workload, while insuring clinical care through no extra false-negative. Flagging causes of 4,373 samples were investigated by manual slide review, after having been run on ADVIA 2120i. A set of 6 user-adjustments is proposed. By implementing all recommendations that we made, false-positive rate falls from 81.8% to 58.6%, while PPV increases from 18.2% to 23.7%. Hence, use of such optimized thresholds enables us to maximize efficiency without altering clinical care, but each laboratory should establish its own criteria to take into consideration local distinctive features.

The purpose of this article is to describe the setting up of 15 blood gas analyzers GEM(®) Premier™ 4000 (IL) at Montpellier hospital. This experience includes analytical characterization (within and between run coefficient of variation) using GSE and GHE IL controls, correlation of 35 samples with a routinely used laboratory blood gas analyzer (Cobas b221, Roche(®)). We shall also develop the training, the habilitation and its follow-up for the user staff (450 people) of the different hospital's units in the aim of the accreditation.

Neurological soft signs (NSS) include anomalies in motor integration, coordination, sensory integration and lateralization and could be endophenotypic markers in autism spectrum disorders (ASD). Their characterization provides a more precise phenotype of ASD and more homogeneous subtypes to facilitate clinical and genetic research. Few scales for NSS have been adapted and validated in children including children with ASD. Our objective was to perform an adaptation to the child of a scale assessing neurological soft signs and a validation study in both general and clinical populations.We have selected the NSS scale of Krebs et al. (2000) already validated in adults. It encompasses 5 dimensions: motor coordination, motor integration, sensory integration, involuntary movement, laterality. After a preliminary study that examined 42 children, several changes have been made to the original version to adapt it to the child and to increase its feasibility, particularly in children with ASD. Then we conducted a validation study by assessing the psychometric properties of this scale in a population of 86 children including 26 children with ASD (DSM 5 Criteria) and 60 typically developing children. Children's ages ranged between 6 and 12 years, and patients and controls were matched for gender, age and intelligence. Patients were assessed using the Autism diagnostic Interview-revised and the Childhood Autism Rating Scale to confirm diagnosis. Typically developing children were assessed using the semi-structured Mini International Neuropsychiatric Interview for Children and Adolescents to eliminate any psychiatric disorder. All children with neurological pathologies (history of cerebral palsy, congenital anomaly of the central nervous system, epilepsy, tuberous sclerosis, neurofibromatosis, antecedent of severe head trauma) and obvious physical deformities or sensory deficits that could interfere with neurological assessment were excluded from the study. Both patients and controls were assessed using the Raven Progressive Matrices to exclude intellectual disability, and the adapted Krebs' scale for the assessment of NSS.Adaptation of the scale consisted of a modification in the order of items, in the use of concrete supports for the assessment of laterality and in the elimination of item constructive praxis. The internal consistency was good with a Cronbach alpha of 0.87. Inter-rater reliability was good, kappa coefficient was greater than 0.75 for 16 items, 3 items had a kappa value between 0.74 and 0.60, only 1 item had a kappa coefficient between 0.4 and 0.59. Good inter-rater reliability was also checked for the total score with a value of intra-class correlation coefficient (ICC) of 0.91. Principal component analysis found five factors accounting for 62.96 % of the total variance. About the comparison between patients and controls, significant differences were found for NSS total score (P=0.000) and all subscores.The adaptation for children of the Krebs et al.' NSS scale proved to be valid, especially in children with ASD.

To develop an external quality control procedure for CyberKnife(®) beams. This work conducted in Nancy, has included a test protocol initially drawn by the medical physicist of Nancy and Lille in collaboration with Equal-Estro Laboratory.A head and neck anthropomorphic phantom and a water-equivalent homogeneous cubic plastic test-object, so-called "MiniCube", have been used. Powder and solid thermoluminescent dosimeters as well as radiochromic films have been used to perform absolute and relative dose studies, respectively. The comparison between doses calculated by Multiplan treatment planning system and measured doses have been studied in absolute dose. The dose distributions measured with films and treatment planning system calculations have been compared via the gamma function, configured with different tolerance criteria.This work allowed, via solid thermoluminescent dosimeter measurements, verifying the beam reliability with a reproducibility of 1.7 %. The absolute dose measured in the phantom irradiated by the seven participating centres has shown an error inferior to the standard tolerance limits (± 5 %), for most of participating centres. The relative dose measurements performed at Nancy and by the Equal-Estro laboratory allowed defining the most adequate parameters for gamma index (5 %/2mm--with at least 95 % of pixels satisfying acceptability criteria: γ1). These parameters should be independent of the film analysis software.This work allowed defining a dosimetric external quality control for CyberKnife(®) systems, based on a reproducible irradiation plan through measurements performed with thermoluminescent dosimeters and radiochromic films. This protocol should be validated by a new series of measurement and taking into account the lessons of this work.

A method of separation by gas chromatography with a flame ionization detector was developed for quantifying cocaine in powders seized by the police. The method was validated by studying parameters of calibration, trueness, precision based on trueness error (or systematic bias) and random error. Total error, which is the combination of these errors, is used to confirm the method adequacy with the objectives fixed by the analyst. Accuracy profile is an efficient decision tool to do it. Results obtained with weighted regression model allow concluding that the method fits quantitation of heroin and cocaine in powders on 2 to 100% concentration (w/w) domain with 10% limits of acceptation and a risk of 5%.

The newly developed, high throughput, Vitros 3600 immunoassay system associates different technologies on board: MicroWell (analytes immunocapture), MicroSensor (visible interference analysis), and Intellicheck (real time process control for analytical error detection). During a three months period, Vitros 3600 system, ease of use, practicability and MicroSensor technology efficiency have been tested using the following assays: betaHCG, troponin, ferritin, aHBcT, HBsAg, aHCV, AFP and CEA. Within-day and within-batch, between-calibration precisions are acceptable. Overall assay correlations versus the methods in use in our laboratory are good, despite small numerical differences that never affect clinical interpretation of the results. We have appreciated the system reliability, reinforced by the ease of use (simple software, on-board VDocs, continuous access to reagent and sample loading, reagent stability, very low noise (60 dB)), the quality of the results, MicroSensor and Intellicheck technologies efficiency, the short maintenance time and its traceability, and the very low liquid waste volume (5 L of liquid waste for 1600 tests). In conclusion and considering its practicability, the Vitros 3600 system is fully validated and well suited for our laboratory.

This paper presents the development of a protocol for quality control of a megavoltage cone beam CT imaging system (MVCB) mounted on a Siemens Oncor 6MV linear accelerator.Several parameters were controlled on the MVCB system: (1) the initial geometric calibration of the system; (2) the quality of the images (geometric distortion, uniformity, spatial resolution, low contrast resolution) for various protocols; (3) the correspondence between the intensity of voxels and electronic densities; (4) the dose delivered when achieving a MVCB. These tests were done mainly with two cylindrical phantoms specific to the quality control (QC) of a MVCB system, supplied by Siemens, and with the Catphan 600 phantom (The Phantom Laboratory) and Quasar Multipurpose Body phantom (Modus Medical Devices Inc).The results of the quality control of the images were within the tolerances. The use of the Catphan 600 phantom was inadequate for the QC of MVCB images. These tests also highlighted the need to correct the MVCB images for the "cupping artefact" for dose calculation purpose.The initial characteristics of the MVCB imaging system were established. Such testing also provided the assessment of the influence of various parameters on the image quality as well as the associated dose delivered during their acquisition, and emphasized the corrections needed to use MVCB images for dose calculation.

L-carnitine is a quaternary ammonium compound that facilitates long-chain fatty acids crossing through the mitochondrial membrane allowing their beta-oxidation. Human pathologies relatives to carnitine are mainly deficiencies, with myopathy and lipids metabolism disorders. The aim of this study was to validate the free and total carnitine plasmatic level measurement using the Dimension HM, X-Pand model analyzer (Dade Behring). Free carnitine was directly determined on plasma samples, deproteinized by using ultrafiltration, whereas total carnitine was measured after alkaline hydrolysis. Within-day and between-day imprecision were4,00 and 9,00 % respectively. The method is linear through 250,00 micromol/L and the limit of quantification is 3,00 micromol/L. Our method was correlated to tandem mass spectrometry (r = 0,956 for free and total carnitine). Recovery of free and total carnitine from spiked plasmas was99 %. On board stability of cartridge (5 days) and of calibration (at least 30 days) are in agreement with a method easily adaptable in routine laboratories.

Proteins identified in biological fluids of cancer patients could be helpful for both diagnosis and prognosis. However, clinical proteomics based on analysis of protein profiles in biological fluids has demonstrated various flaws, most of them related to the difficulties met in reproducibility. These difficulties could be partly overcome by accurate standardisation of pre-analytical and analytical steps of these studies. The size of the patient cohort is one of the parameters that determine the powerfulness of the study. Recruitment of a cohort with a sufficient size often implies multicentric studies in which analysis of the reproducibility between centres and standardisation of pre-analytical and analytical steps are essential. Such a standardisation requires the use of calibrated samples as common references.

The treatment with methotrexate at high doses is responsible of many side effects. It's necessary to evaluate serum methotrexate rate to monitor the administration of the methotrexate antagonist, the folinic acid. The aim of this study is to validate the determination of methotrexate in plasma using the automate Xpand Dimension (Dade Behring). Assay results were linearly related to the concentration for the wide range which was examinated (0.15 - 1.4 micromol/L). We report the precision, accuracy, linearity, sensitivity of this assay. The CV was less than 10%. We present the results of correlations with Aca (Dade Behring) and Cobas Mira (Roche). The reagent cartridge in the instrument and the calibration are stable during 28 days.

According to requirements of the French Committee for Accreditation (Cofrac), it is essential to use validated and standardised methods in Immunohematology. This imposes first the knowledge of metrological tolerances for all the technics. Two multicenter studies were carried out to define the maximal acceptable deviations concerning incubation temperature and time, volumes of patient plasma and tests cells for antibody screening using indirect antiglobulin test on one hand and for reverse grouping on another hand. All equipment used (temperature test chamber, chronometer, pipettes) were calibrated according to Cofrac standards. The antibody screenings were performed manually using 3 different filtration systems: ID Diamed, Biovue Ortho and Scangel Biorad, the same tests cells, a standard 20 ng/mL anti RH1, a positive control anti KEL1 and a negative control; the reverse blood grouping was performed manually using the above mentionned filtration systems and microplate technic with the same A1 and B test cells. These two studies showed that all the tests from the multiples combinations of the above parameters gave the same results and allowed us to define a range of tolerance for 4 critical physical parameters involved in the antibody screening and blood typing.

Although the reliability of the electronic apex locator is agreed upon in the endodontic literature, the general practitioner has difficulties to integrate the device in his daily practice. The authors of this paper conclude that the apex locator should be used to confirm the information obtained from the pre-operatory radiograph (imperatively taken with the parallel technique) and they assert that the data obtained electronically have still to be interpretated. The apex locator can be considered an essential tool as long as its limitations are known.

The decimal visual acuity chart is not easy to use for statistical analysis and requires a transformation into LogMAR units (decimal logarithm of the Minimum Angle Resolution). In contrast to the decimal chart, the logarithmic chart has an arithmetic progression and a constant interval between lines. The LogMAR chart makes statistical analysis of visual acuity easy. Change in visual acuity is calculated directly by subtracting LogMAR data, while the average visual acuity is obtained with the arithmetic mean value of the LogMAR data. The mean acuity expressed in LogMAR units can be transformed into a decimal chart for a more comprehensive result. To calculate the average visual acuity directly from the decimal data, the geometric mean value must be used instead of the arithmetic mean value.

The Advia 70 hematology system is a new automated analyser manufactured in Texas (USA) by MWI-DANAM and marketed by Bayer- Diagnostics in France. The throughput is 70 complete blood counts (CBC) with leukocyte differential counts (diff) per hour. Three sample modes are proposed: normal mode (180 muL of whole blood), sample saver mode (90 muL) or automatic sampler (180 muL). The principles used on Advia 70 are: 1) electrical impedance for cell counting (WBC, RBC, platelets, MCV) and RBC/plt sizing; 2) multi-dimensional optical system and absorbance for white cell differential. The Advia 70 has been evaluated in our laboratory over a three-week period. Within-run variations of blood counting (CBCdiff) were determined on normal and abnormal patient specimens whereas between run-variations were determined on normal controls. Linearity and detection limits were also tested. The Advia 70 system results were reproducible and reliable. The correlations between the various sample modes were very good. Contamination and store assays were performed. Thirty normal and abnormal samples were successively analysed on the Advia 70 system and on the Advia 120 system which methodologies are different (myeloperoxidase staining coupled with flow cytometry-nuclear lobularity analysis for WBC/Diff, flow cytometry and laser diffraction for RBC/platelets), and the results were compared: despite the different technologies used on both analysers, the correlations were very good (CBC and diff parameters). Finally, we evaluated the leukocyte differential flags on 72 patients samples with abnormal cells, using the blood smear examination as the reference method. In conclusion, the Advia 70 can be used in private and hospital laboratories.

Diagnosis and management of hypertension is based on blood pressure (BP), as measured by auscultatory method. However, the devices are rarely checked making the quality of the measures doubtful.To compare BP measured according to the WHO recommendations using 2 different devices: the mercury or aneroid sphygmomanometer used by the physician and a SECURUS manometer that has been calibrated just before the implementation of the study.This is a randomised study performed with 1,336 French general practitioners (GP). Each GP received a calibrated SECURUS before the start of the study and was asked to include 2 treated hypertensive patients and one newly diagnosed patient. BP was measured 3 times with each device at 2 different visits. The devices were used in a random order: the order, at the 1st visit, was always the same for all the patients for a given GP. At the second visit the order of the devices was reversed. Patients were classified as normal (BP140/90 mm Hg) or high BP with each device at each visit.3,992 patients were included in the study (2,751 treated hypertensive patients). SECURUS BP measures were rounded up to 0 or 5 by 69% of the GPs and BPs with their own device by 77% of the GPs. A difference between the 2 devices5 mmHg was observed in nearly 10% of the GPs for SBP and 4% of the GPs for DBP. At the second visit, 13% of the treated hypertensive patients and 12% of the newly diagnosed patients and in whom no antihypertensive drug treatment has been introduced were not classified as having normal or high BP value in the same way by the 2 devices.This study confirms the results of a previous pilot study and emphasises the need of BP measurements respecting the guidelines in clinical practice, because of the possible impact on patient care and related costs.

The large metrological variation (CV, about 25%) observed between laboratories, at the national French level, for the measurement of enzymatic activities results in a loss of efficiency in using laboratory results. Current data show that the standardisation of methods is insufficient to solve this problem and needs to be completed by an harmonisation of the practices including the use of a common reference (calibrator). The present work, carried out by the joint working group between laboratories of the Centres for Periodic Health Examination and the French Society of Clinical Biology (SFBC), deals mainly with the feasibility and evaluation of the improvement of the consistency of the results. Twenty laboratories participated in this study. Five independent surveys were conducted during an height month period. Two enzymes were selected because of their clinical importance and their interest in prevention, screening, diagnosis or epidemiology: ALT (alanine aminotransferase) and GGT (gamma-glutamyltransferase). In each survey three kinds of samples i.e. control sera, candidate calibrators and human serum pools, each of them at two levels of activity (one physiological and the other pathological) were measured in duplicate. The low intra-laboratory imprecision and the high degree of the standardisation of used methods, due to an important effort previously done in this field, permitted to consider a common calibration. The stability and mainly the commutability, i.e. the ability for the candidate calibrator to show a behaviour similar to that of human samples towards the used methods, allowed to reduce the inter-laboratory variation by a half to two third-fold, reaching a coefficient of variation5% similar to those observed for cholesterolemia or glycemia. This level of consistency should permit to use common reference limits and common decision limits, after validation of this approach in real practice. The consequences of the harmonisation of practices, extended to the all laboratories, exceed largely the scope of this study. The reduction of the uncertainty and a better approach of the accuracy for the measurement of enzymatic activities should led to a real benefit for the patients in terms of prevention, screening, diagnosis or therapeutic monitoring and consequently for the public health.

We used 3D ultrasonographic reconstruction with manual acquisition to study the volume of venous clots in vitro.Native 2D ultrasound slices were acquired free hand for 3D reconstruction. The spatial coordinates of each slice were delivered in real time with an electromagnetic captor. We applied a standard ultrasound protocol to test the calibrated 3D reconstruction quantitatively. The volume of 5 clots of increasing size was quantified in vitro using manual segmentation in a double-blind manner by two independent operators.The comparison tests and the interoperator regression lines evidenced good agreement between real and measured volumes, confirming the coherence of the reconstruction protocol and the feasibility of this technique in a routine medical setting. Intraoperator variability was 7 to 11% and interoperator variability 16.9%.This calibrated 3D reconstruction is compatible with in vitro measurement of venous clots. This technique could be useful to follow the evolution of the head of proximal deep vein thrombi in vivo. It will be more reliable with semi-automatic or even automatic segmentation becomes available.

We have developed a new per-operative three dimensional (3D) reconstruction technique to evaluate the 3D correction of a scoliotic spine induced by surgery using Cotrel-Dubousset instrumentation. A small object with 15 embedded markers was used to calibrate the radiographic system. During surgery, the calibration object was sterilized and fixed to the patient just before the acquisition of two pairs of posterior-anterior and sagittal radiographs; one pair before the rotation maneuver of the rod and one pair after the maneuver. The markers were digitized on each radiograph and their relative 3D positions were measured to establish the relation between the 3D positions of the anatomical structures and their 2D positions on the radiographs. This relation was used to calculate the 3D position of six anatomical landmarks per vertebra (the centers of the superior and inferior vertebral body endplates and the proximal and distal bodies of both pedicles) from the identification of these landmarks on each radiograph. We made a 3D representation of the thoracic and lumbar spine of three patients with idiopathic scoliosis undergoing corrective surgery by the posterior approach. Clinical indices (Cobb angle, axial rotation and the plane of maximum curvature) computed from the 3D reconstruction of the spine obtained before and after the rotation maneuver of the rod were compared to evaluate the 3D correction performed during the surgery. The new proposed approach allows the surgeon to evaluate the per-operative shape of the spine. This approach is simpler, faster and less risky for the patient than the previous method which employed an electromagnetic digitizer to measure the 3D coordinates of anatomical landmarks located on the posterior part of the spine. Furthermore, the 3D representation of the spine visualized from different points of view gives the surgeon an accurate evaluation of the 3D correction during the surgical procedure.

Bone densitometry is a biological measurement which must comply to the usual rules of quality control. Calibration phantoms are available and must be regularly measured. Results may be interpreted by visual inspection or by estimating drift percentage. Different calculation methods have been proposed. A rigorous procedure is required when replacing densitometry devices. Simple and regular controls can assure the reliability of the technique.

The reliability of results given by specific IgE dosages technology is conditioned by the quality of the technology used. Analytical comparison of two techniques (Pharmacia CAP System and Alastat-DPC) shows important behaviour differences in the evaluation of the precision/reproducibility of results and in dilution tests. The Pharmacia CAP System demonstrates qualities comparable to those awaited from any immunodiagnostic test. The Alastat techniques shows high imprecision and the dilution tests make us wonder about calibration and/or ability of the support used to fix all epitopes.

The results, either positive or negative, of the ELISA tests performed on blood donors to detect viral markers, are always validated by reading microplates on photometers. In Rennes, these microplates can be read on MR 7000 (Dynatech) or IEMS (Labsystems) photometers. This step, the last one in the technical sequence, conditions the results. Regular checking of the photometers therefore may enhance the quality of the testing sequence. To check the quality of the photometers, we use a 96-well microplate, the "Universal Calibration Test Plate" marketed by BIO-TEK Instruments USA. The plate includes 8 blank wells, 6 wells equipped with glass filters (3 stained and 3 unstained). This plate comes with a table showing the optical density in relation to the wavelength. We first verify the repeatability of each photometer, and secondly, verify accuracy. The plate also permits verifying the linearity of each photometer. In view of the results, we were able to state that both photometers were accurate, since the results obtained were compatible with an optical density of +/- 0.024 +/- 1%. Do. The tests are repeatable, with a variation coefficient below 0.5%, linearity was verified (r: 0.999 for both photometers). Reading the plate only takes a few minutes and permits daily control of the photometers. It only requires that the test results be reported on a control card to follow-up possible deviations, and technical maintenance can thus be carried out immediately.

Different methods are available to measure non-allergic airway responsiveness. In the last years, efforts have been made to improve standardization of these methods, in order to allow comparison of data from different sources. The most currently used bronchial provocation tests are those with nebulisation of histamine or methacholine either a tidal volume or from a dosimeter, a dose-response curve being obtained in measuring expiratory flows or airway resistance. Inhalation of non-iso-osmolar solutions, cold air hyperventilation, exercise or other agents and stimuli may be used to estimate airway response, but they are more useful as a research tool than for clinical purposes. The reproducibility of bronchial provocation tests is dependent of different factors such as those related to the subject (asthma stability, performance of tests, medications, circadian variations), technical factors (type and calibration of the apparatus, nebulizer output, measurements, solutions) and to the methods of calculation of the bronchial response. Short-term reproducibility of the different types of bronchial provocation tests is usually good although long-term stability needs to be further assessed. A correlation has been reported between the response to most of the different bronchoconstrictor agents, although variable.