BACKGROUND:Urine sediment analysis is a frequently ordered test, since it permits screening for many clinical conditions. Here, the technical and bacteriuria diagnostic performance of FUS-200, a new sediment analyzer, was assessed.METHODS:Carry-over, imprecision, and linearity were measured according to CLSI protocols. FUS-200 was compared to sediMAX™, our current laboratory analyzer, in terms of particle recognition/counting in 382 fresh urine samples, and bacteriuria diagnosis was based on white blood cell (WBC) and bacteria counts in a subgroup of the same samples. In the diagnostic study, quantitative bacterial cultures served to classify the samples as bacteria-positive or bacteria-negative.RESULTS:FUS-200 did not show carryover for the particles tested. Total imprecision for red blood cells (RBCs) and WBCs in positive controls was 3.6%-10.5% and complied with European guidelines. RBC and WBC recovery was linear. When FUS-200 particle counts were edited by a reviewer, concordance with sediMAX improved for epithelial cells, yeast, and crystals, and recognition of casts and crystals improved. FUS-200 concordance with sediMAX varied between 97% for yeast and 58% for bacteria and was satisfactory. FUS-200 detected bacteriuria better than sediMAX (P = 0.004). FUS-200 WBC and bacteria cutoff values based on the Youden index detected bacteriuria better than manufacturer cutoffs. The best sensitivity with which FUS-200 detected bacteriuria was 79%.CONCLUSIONS:Although casts and crystal recognition should be improved, the overall technical performance of FUS-200 was acceptable to good. FUS-200 exhibited good screening accuracy for bacteria and WBC. Editing only mildly influenced FUS-200 outcomes.

BACKGROUND Analytical performance of 24 Beckman-Coulter AU 5800 methods was verified against recognized quality goals and manufacturer's expected imprecision and bias. METHODS AU5800 method imprecision, bias, agreement with a comparative method, and linearity were studied using CLSI protocols, commercial control material, patient samples, and linearity test kit solutions. Repeat patient testing and IQC were also used for imprecision. Commutability of control material was tested. Total analytical error (TAE) was estimated for each method and between the tested and the comparative method, the Beckman-Coulter Unicel DxC800. RESULTS CLSI EP15 total imprecision CV (TCV) < 3.2%. Duplicate patient imprecision CV < 2.8%. IQC imprecision CV < 5.1%, except for low level ALP (CV = 7.4%). Sodium and urate IQC imprecision were higher than manufacturer's specifications. TAE for all methods met accepted quality goals. Correlation between methods was > 0.975, except for Cl (0.971), TP (0.964), and Na (0.948). Average bias versus Unicel DxC800 is high for ALP (17.3%), GGT (37%), LD (20%), TBIL (-23%), and TP (8%) and was confirmed in other laboratories. TAE between methods met allowable total error for 21 analytes. For GGT, between method TAE (23 to 51%) was predictable from expected bias and combined method imprecision. For LD and TP several between method differences were outside boundaries describing expected bias. Linearity was excellent with R2 > 0.997 and deviations met accepted goals. CONCLUSIONS The Beckman-Coulter AU 5800 demonstrates good linearity, low imprecision, and good correlation with previous methods. Observed between method differences suggest ALP, GGT, LD, TBIL, and TP harmonization should be considered.

Abstract Background: Serum creatinine is important for detecting the beginning of a decline in kidney function. The Beckman Coulter Jaffe reagents for measuring creatinine have been standardized to the internationally accepted reference method: isotope dilution mass spectrometry (IDMS). The impact of this recalibration on the Beckman Coulter® modular or cup (stat) Jaffe method is studied. Methods: Recalibrated Jaffe (calibrator set points IDMS traceable) and classic National Institute of Standards and Technology (NIST) creatinine methods (traceable to NIST 914a) were compared with an enzymatic method (Sentinel, traceable to NIST SRM 967). All measurements were performed on Synchron DxC 800 systems. Imprecision of the routine methods was studied using the Clinical and Laboratory Standards Institute (CLSI) protocols and laboratory quality survey. Thirteen plasma pools, with concentrations <354 μmol/L, were analyzed with a gas chromatography isotope dilution mass spectrometry (GC-IDMS) method and routine methods. Total error of 8.2% based on biological variability, set on the GC-IDMS values and acceptance criteria (bias <5%, imprecision <8% at concentrations ≥88.4 μmol/L and a maximum 10% increase in the relative error of estimated glomerular filtration rate (eGFR) of the National Kidney Disease Educational Program (NKDEP) were used for evaluating analytical performance of the routine methods studied. Results: After recalibration of the Jaffe method, median bias (μmol/L) decreased from 12.4 (95% CI: 9.1–21.2) to 7.3 (95% CI: 1.5–10.5). Imprecision of the Jaffe method is in agreement with the claim of the manufacturer, namely <9 μmol/L or <3% below or above 292 μmol/L. Below creatinine of 88.4 μmol/L, imprecision of the recalibrated Jaffe and enzymatic methods is between 4.1% and 6.9%, and 5.0% and 7.1%, respectively, and significantly different (p=0.02 for both the Jaffe and enzymatic methods) from the goal, based on biological variability, of 2.7%. For the adult pools, all recalibrated Jaffe and enzymatic results fall within the total error of 8.2%. In the pediatric samples, one-third of the recalibrated Jaffe and three of the six enzymatic results fall within this total error goal. Conclusions: Recalibration significantly reduced bias of the Jaffe method. For pediatric samples, recalibrated Jaffe results do not comply with either the imprecision goal or the total error based on biological variability. Adult recalibrated Jaffe results are in compliance with the goals based on biological variability and with the acceptance criteria from the NKDEP.

Background: Reliable laboratory methods for detecting congenital CMV infection are valuable since CMV infections are asymptomatic and because early detection is important for correct management and counseling of expectant mothers.Objectives: Compare the Beckman Coulter Access (R) method for the Unicel (R) DxI 800 analyzer with the bioMerieux VIDAS (R) method for two serological markers: CMV IgG and CMV IgM.Study design: Precision was determined with CLSI EP5-A2 protocol. Linearity of the Access CMV IgG was evaluated using selected high positive samples. Performance was assessed by testing non-selected pregnant women, frozen negative and positive samples with recent and old infections. Kinetics of the anti-CMV antibodies response was studied using samples from pregnant women with a recent infection. In a prospective study, 3992 pregnant women were screened for determining prevalence of a primo-infection and CMV IgM non-specific rate.Results: Total CV is lower than 10% and 12% for Access CMV IgG and CMV IgM. The IgG method is linear (R-2 = 0.999) with recoveries between 85% and 108%. Correlation between Access and VIDAS CMV IgG is highly significant (P < 0.001). Observed agreement was 97.4% for CMV IgG and 93.7% for CMV IgM. Relative sensitivity and specificity was 97.2% and 100% for IgG and 100% and 97.4% for IgM. Kinetics of the antibody response measured with Access methods is significantly higher (P < 0.02) when compared with VIDAS and probably easier to interpret. Prevalence of a recent infection was 0.85% and CMV IgM non-specific rate was 2.9%.Conclusion: Good sensitivity and specificity and pronounced anti-CMV antibody response make the Access CMV IgG and IgM tests suitable for screening prenatal CMV infections. (C) 2010 Elsevier B. V. All rights reserved.

BACKGROUND:The choice of parameter sets used to calculate Down's syndrome risks is important. This study details analysis of samples from affected and unaffected pregnancies and evaluates whether published population data is optimal. Screening efficiency realized with measurement procedure-specific population parameters is compared with selected population sets available in the literature.METHODS:In a retrospective experiment, double and triple testing was performed on maternal serum samples from 286 randomly chosen unaffected singleton pregnancies and 95 Down's syndrome affected pregnancy samples. Using a risk cut-off of 1 in 250, detection rates and false positive rates were estimated for different population settings to select a model giving the best overall efficacy. Receiver operation characteristics curve analysis was performed and detection rates realized with the different population settings was estimated at a 5% fixed false positive rate.RESULTS:Geometric mean weight corrected multiples of the median values were 1.01 for alpha-fetoprotein (AFP), 1.02 for human chorionic gonadotropin (hCG) and 1.01 for unconjugated estriol (uE3) in unaffected pregnancies and 0.77 (95% CI: 0.71-0.83) for AFP, 2.42 (95% CI: 2.17-2.71) for hCG and 0.78 (95% CI: 0.73-0.83) for uE3 in affected pregnancies. Differences in double and triple risks obtained with the different models were significantly different from each other (p < 0.001). At a cut-off of 1 in 250, the maximum triple test detection rate was 75.8% for a false positive rate of 4.9% and was obtained with the measurement procedure-specific setting. At a fixed false positive rate of 5%, the maximum detection rate for the triple test was 77.9% (95% CI: 62.2%-85.8%). The maximum double test detection rate at 5% false positive rate was 69.6% (95% CI: 59.5%-78.5%). Except for two models, the area under the curve for the triple test was higher than that of the double test.CONCLUSIONS:The Access triple test meets the typical performance characteristics for this test combination. The assay-specific settings yielded the overall best efficacy for the criteria studied. Therefore, the availability of measurement procedure-specific mid-trimester reference values for unaffected and affected pregnancies in prenatal screening programs is essential. Such reference values are established for the Beckman Coulter Access triple test: maternal serum AFP, uE3 and hCG.

OBJECTIVE:Choice of parameter sets used to calculate Down's syndrome risks is complicated. Published population statistics were compared with assay-specific parameters to optimise screening efficiency. DESIGN:Weight-corrected Gaussian population statistics for alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG) and unconjugated oestriol (uE(3)), expressed as log(10) multiples of median (MoM) were established for a Belgian cohort of 748 unaffected pregnancies. Using Cuckle's method and Access-specific data, Down's syndrome parameters were tailored to the Belgian cohort. Correlated marker triplets for affected and unaffected pregnancies were modelled and combined with maternal age to calculate term risks for Trisomy 21. Receiver-Operator-Curve (ROC) analysis was performed to identify the optimally-performing population set. RESULTS:Log-normal distributions for the Access markers had geometric mean MoM values close to zero and standard deviation values equal to 0.1460 (AFP), 0.2185 (HCG) and 0.1317 (uE(3)). Correlation between AFP and other markers was significant (p < 0.001). Correlation between HCG and uE(3) was not significant (p = 0.4818). The median ratio between the lowest and highest risk outcomes for the test MoM set was 4.3. Areas under ROC curves differed significantly (p < 0.001) between the models and the analyser-assay specific parameters resulted in the largest area. At a 1 in 250 threshold, sensitivity and specificity were 69% and 96%. At false-positive rates (1-specificity) = 5%, sensitivity was 72.5%. CONCLUSION:Population parameters significantly affect risk outcome and hence screening performance. Highest efficiency may be obtained with parameters tailored to an assay-specific population model. Consequently models from literature, without knowledge of the assay/analyser combination may lead to suboptimal performance.

Objectives: To establish gestational age-specific mid-trimester normal medians for the prenatal serum markers a fetoprotein (AFP), human chorionic gonadotropin (HCG) and unconjugated oestriol (uE3) for a Belgian population by using the Beckman Coulter Access chemiluminiscent immunoassays; to compare these data with data obtained from other geographical regions; to propose regression coefficients for regressed medians and analyse variation induced by different regression equations; to evaluate the effect of formulas used for gestation correction on estimating risk in Down's syndrome.Design: Data derived from 862 fresh serum samples from women being screened for Down's syndrome pregnancy, composed of selected pregnancies deemed to be normal, were examined in a retrospective study. Regressed medians were calculated by using a first-degree logarithmic-linear fit of the raw data. Multiples-of-median (MoM) values estimated by using a simple logarithmic-linear equation were compared with those calculated with higher-degree polynomials chosen with a goodness-of-fit analysis. Model-specific variation was estimated and the effect on risk for Down's syndrome was evaluated.Results: Regressed medians (Y) for Access serum markers AFP (IU/ml), HCG (IU/ml) and uE3 (nmol/l) for a Belgian population can be estimated with the equation Y = 10(A+BX) with X = decimal weeks. The best fit was obtained with a third-degree and a second-degree polynomial for AFP and uE3, respectively. Differences between the medians and among the slopes of the geographical populations were found to be significant (analysis of covariance, p < 0.001).Conclusions: Belgian marker medians versus gestational time are found to show a pattern that is similar to that in the literature. The log-linear equation is observed to give a good fit and can be suggested as a tool for calculating median MoM values for Belgian laboratories that use Access biochemical prenatal markers.

Background: Adjusting maternal serum markers for maternal weight is considered to be a standard practice when screening for pregnancies associated with Down's syndrome. The choice of model for taking maternal weight into account is, however, rarely explicitly evaluated.Method: The relationship between the maternal serum markers alpha fetoprotein (AFP), human chorionic gonadotropin (HCG) and unconjugated oestriol (uE3), determined with the Beckman Coulter access reagents and maternal weight was investigated in a cohort of 752 Belgian women being screened for pregnancy associated with Down's syndrome. Two different models (the log-linear equation and the linear-reciprocal equation) were used to determine the relationship between the serum markers and maternal weight.Results: A significant relationship between log(10) multiples of median (MoM) values and weight ( kg) was obtained for all markers, and the log-linear model had higher coefficients of determination (r(2)) when compared with the linear-reciprocal model. Weight correction with either method achieved the optimum effect that the correction factor for a woman with a population median weight of 65.5 kg was not significantly different from 1. Simulated weight-corrected MoM values with the two approaches were compared and variation was estimated. The mean difference between the weight-corrected MoM values calculated by the two methods was 7.8% (SD 4.3%) for AFP, 14.0% (4.4%) for HCG and 5.9% (3.2%) for uE3. This resulted in a difference in risk estimate of 1.66-5.34% for Down's syndrome owing to weight correction algorithm differences in women of median weight.Conclusion: The log-linear weight correction approach was shown to be marginally more effective by a goodness-of-fit analysis. Differences in weight-corrected MoM values estimated with the two approaches are highly significant (p < 0.0001, Wilcoxon's paired sample test), but the effect on risk calculation was not significant. It was observed that the changes in risk became significant the more the MoM correction factors deviated from 1.

Background This report describes a nephelometric assay for measuring complement 3d (C3d).Methods C3d was separated from C3 and the other C3 split products by polyethylene glycol precipitation. The supernatant containing C3d was then measured by rate nephelometry in a Beckman Immage rate nephelometer using a specific antibody. Calibration was performed with dilutions of a standard, which was obtained by incubating a serum pool at 37degreesC for 7 days. This incubation step allowed the activation and breakdown of C3 into C3d.Results The assay was linear across the normal and pathological range. Precision studies showed within-run and between-run coefficients of variation of <5% and <6%, respectively. The nephelometric results are comparable with those obtained by radial immunodiffusion. Neither haemoglobin nor lipids interfere with the assay.

We describe three monoclonal IgM paraproteins for which nephelometric IgM quantification generated inaccurate results.

The toxicity of heavy metals (Cd, Co, Cu, Cr, Hg, Ni, Zn), acid-iron waste, pentachlorophenol, and γ-hexachlorocyclohexane on the marine nematode Monhystera disjuncta has been studied in laboratory assays. High levels of toxicants (< 1 mg/l) are necessary to cause acute effects on J2-larvae. The relative toxicity as measured by development retardation and reduction of fecundity is compared with threshold concentrations obtained from the acute tests. Fecundity is the most sensitive indicator. LC 50 values correlated significantly with the minimum concentrations of metals causing mortality and developmental inhibition. Ranking of toxicity based on fecundity does not correlate with ranking based on mortality or development rate. Monhystera disjuncta exhibits high resistance to pollutants compared with other benthic organisms.

Diplolaimella dievengatensis sp. n. was sampled from the Dievengat, a thalassic water pond situated near Knokke in North Western Belgium. The different juvenile and adult stages are described in detail. The male of D. dievengatensis is characterised by the length of the spicules ( > 25 μm), the prominence of the gubernacular apophyses and the presence and position of five pairs of equal and prominent post-cloacal genital papillae. The female is characterised by the sclerotizations of the vaginal cuticle and the absence of a postvulval uterine sac.

The influence of temperature, food and hexavalent chromium on mortality and developmental rate was determined for the J2-larvae of the marine bacterivorous nematode Monhystera disjuncta. When mortality was considered, temperature significantly influenced chromium toxicity (P≤0·001), whereas food did not effect chromium toxicity. When development inhibition is used as the toxicity criterion, both temperature (0·001≤P≤0·01) and food (P≤0·001) influenced chromium toxicity. The interaction between temperature and food is not significant for both criteria studied. It is concluded that environmental variables (abiotic and biotic) influence chromium toxicity and that this has to be taken into account in hazard assessment studies.

An energy budget was constructed for the marine nematode Monhystera disjuncta. Respiration was measured with a modified Cartesian diver technique, in which the nematodes were kept in agar inside the diver 'head'. The relationship between respiration and body weight was: R =1.53 W. Body growth was exponential during the juvenile phase, with a growth rate equal to 0.61 d. After maturation the growth rate fell to 0.17 d. Food uptake was measured in experiments with radiolabeled bacteria. In one series of experiments the accumulation of radiolabel in the nematodes was followed. In a second series the decrease in labeling was followed when pre-labeled nematodes fed on unlabeled bacteria. A model for label uptake permitted the calculation of assimilation efficiency and consumption rates. Consumption rates thus measured, correspond well to those calculated from the growth, reproduction and respiration rates. Assimilation efficiency was low, around 25%. Production efficiency (P/(P+R)) was high: 60% for the population at stable age distribution, and up to 75% for reproducing females. This seems to be a general feature in nematodes.

Aspects of the demography of Monhystera disjuncta were investigated at different temperatures (in agnotobiotic cultures) and in different feeding conditions (monoxenic cultures with different bacterial strains, and different densities in the feeding suspension with one strain). Embryonic development time, minimum generation time, egg deposition rate and adult longevity depend on temperature, quality and quantity of food offered. Body mass at maturity is an allometric function of food density. It is shown that a previously inferred selectivity in food uptake is an artifact of culture conditions. pH buffering and addition of sterols permit culture of the species on a wide variety of bacterial strains. M. disjuncta is less well adapted to take advantage of high food density than are nematodes from polysaprobic environments. The animals channel surplus energy intake into a larger body mass, without being able to increase their rate of population growth accordingly.

Aspects of the demography of Monhystera disjuncta were investigated at different temperatures (in agnotobiotic cultures) and in different feeding conditions (monoxenic cultures with different bacterial strains, and different densities in the feeding suspension with one strain). Embryonic development time, minimum generation time, egg deposition rate and adult longevity depend on temperature, quality and quantity of food offered. Body mass at maturity is an allometric function of food density. It is shown that a previously inferred selectivity in food uptake is an artifact of culture conditions. pH buffering and addition of sterols permit culture of the species on a wide variety of bacterial strains. M. disjuncta is less well adapted to take advantage of high food density than are nematodes from polysaprobic environments. The animals channel surplus energy intake into a larger body mass, without being able to increase their rate of population growth accordingly.

The toxicity of bipartite Hg, Cu, Zn and Ni metal mixtures was studied to the free-living marine nematode Monohystera disjuncta. Observed mortality and developmental inhibition responses could not be predicted by independent dissimilar nor simple similar action. The toxic unit concept was also used to evaluate overall mixture toxicity. With regard to mortality all paired metal mixtures act in a less than additive manner. The developmental inhibition response was not so clear-cut: the ZnNi mixture acts synergistically; similarly the joint effect of ZnCu combinations and CuNi mixtures, containing small amounts of Cu (1 mg litre−1), act synergistically and the response type with regard to the HgCu mixture is not very clear.