Feasibility of different mass spectrometric techniques and programs for automated metabolite profiling of tramadol in human urine

The purpose of the study was to determine the advantages of different mass spectrometric instruments and commercially available metabolite identification programs for metabolite profiling. Metabolism of tramadol hydrochloride and the excretion of it and its metabolites into human urine were used as a test case because the metabolism of tramadol is extensive and well known. Accurate mass measurements were carried out with a quadrupole time-of-flight mass spectrometer (Q-TOF) equipped with a LockSpray dual-electrospray ionization source. A triple quadrupole mass spectrometer (QqQ) was applied for full scan, product ion scan, precursor ion scan and neutral loss scan measurements and an ion trap instrument for full scan and product ion measurements. The performance of two metabolite identification programs was tested. The results showed that metabolite programs are time-saving tools but not yet capable of fully automated metabolite profiling. Detection of non-expected metabolites, especially at low concentrations in a complex matrix, is still almost impossible. With low-resolution instruments urine samples proved to be challenging even in a search for expected metabolites. Many false-positive hits were obtained with the automated searching and manual evaluation of the resulting data was required. False positives were avoided by using the higher mass accuracy Q-TOF. Automated programs were useful for constructing product ion methods, but the time-consuming interpretation of mass spectra was done manually. High-quality MS/MS spectra acquired on the QqQ instrument were used for confirmation of the tramadol metabolites. Although the ion trap instrument is of undisputable benefit in MS(n), the low mass cutoff of the ion trap made the identification of tramadol metabolites difficult. Some previously unreported metabolites of tramadol were found in the tramadol urine sample, and their identification was based solely on LC/MS and LC/MS/MS measurements.

Establishment of an indocyanine green test using an automatic chemistry analyzer

The indocyanine green (ICG) clearance test has been used to assess the reserve of hepatic function. This method is based on the spectrometric measurement of its plasma concentration at maximum wavelength of 805nm, which requires a spectrophotometer and associated maintenance. We established an ICG clearance test using a Toshiba 200FR automatic chemistry analyzer that can be tuned to a wavelength of approximately 805nm. Five pooled sera spiked from 0 to 4.0mg/dL were analyzed for linearity test and precision was determined at five levels in the range 0.1–2.0mg/dL. The ICG retention rate at 15min (R15) was determined for 38 patients using a conventional method and our method. The ICG clearance test using the automatic chemistry analyzer showed good linearity, and precision ranged from 0.3% to 1.0% for within-run CVs and from 0.6% to 4.7% for total CVs. The degree of agreement between the two methods was also acceptable (mean difference of 1.5%). It is expected that the ICG test using the automatic chemistry analyzer can replace the conventional ICG clearance test, considering the excellent agreement, good precision and linearity over a clinically relevant range.

Sequence determination of lychnin, a type 1 ribosome-inactivating protein from Lychnis chalcedonica seeds

The complete amino acid sequence of lychnin, a type 1 ribosome-inactivating protein (RIP) isolated from Lychnis chalcedonica seeds, has been determined by automated Edman degradation and ESI-QTOF mass spectrometry. Lychnin consists of 234 amino acid residues with a molecular mass of 26 131.14 Da. All amino acid residues involved in the formation of the RIP active site (Tyr69, Tyr119, Glu170, Arg173 and Trp203) are fully conserved. Furthermore, a fast MALDI-TOF experiment showed that two out of three cysteinyl residues (Cys32 and Cys115) form a disulfide bridge, while Cys214 is in the thiol form, which makes it suitable for linking carrier molecules to generate immunotoxins and other conjugates.

[Adaptation of Biomerieux enzymatic UV ammonia on Konelab analysers]

INTRODUCTION

Circulating ammonia in normal patients is relatively low, despite the fact that ammonia is continually produced from endogenous amino acid metabolism. The physiopathological interest of plasmatic ammonia determination lies primarily in its relationships to hepatic insufficiency (cirrhotic or neoplasic), or the diagnosis and the forecast of the Reye's syndrome.

OBJECTS

This study describes an evaluation of plasmatic ammonia determination by the UV end point enzymatic method using GLDH on KONELAB(TM) analyzers.

METHODS

The glutamate dehydrogenase (GLDH : EC.1.4.1.3) catalyses the reducing amination of alpha-cetoglutarate in the presence of NH(4)(+) and of NADPH, H(+) to form glutamate and NADP(+). The reduction of NADPH,H(+)'s concentration, directly proportional to ammonia rates, is evaluated at 340 nm. All the conditions were met to optimize the method, while covering a satisfying field of measurement.

RESULTS AND COMMENTS

The evaluation of the modified method showed a good precision (repeatability: CV < 4 %; interserial reproducibility: CV from 2.01 to 2.93 %; Intraserial reproducibility: CV equal to 0.67%) and a very good accuracy. The field of measurement extends from 27 to 250 micromol/L, with a limit of detection (L(D)) lowered to 0.325 micromol/L.

CONCLUSION

The adapted technique is simple, fast, inexpensive and especially automatizable. It is in addition reliable and chiefly more sensitive, adapting particularly to the determination of plasmatic ammonia in urgency as in routine within our laboratory.

A new automated colorimetric method for measuring total oxidant status

OBJECTIVES

To develop a new, colorimetric and automated method for measuring total oxidation status (TOS).

DESIGN AND METHODS

The assay is based on the oxidation of ferrous ion to ferric ion in the presence of various oxidant species in acidic medium and the measurement of the ferric ion by xylenol orange. The oxidation reaction of the assay was enhanced and precipitation of proteins was prevented. In addition, autoxidation of ferrous ion present in the reagent was prevented during storage. The method was applied to an automated analyzer, which was calibrated with hydrogen peroxide and the analytical performance characteristics of the assay were determined.

RESULTS

There were important correlations with hydrogen peroxide, tert-butyl hydroperoxide and cumene hydroperoxide solutions (r=0.99, P<0.001 for all). In addition, the new assay presented a typical sigmoidal reaction pattern in copper-induced lipoprotein autoxidation. The novel assay is linear up to 200 micromol H2O2 Equiv./L and its precision value is lower than 3%. The lower detection limit is 1.13 micromol H2O2 Equiv./L. The reagents are stable for at least 6 months on the automated analyzer. Serum TOS level was significantly higher in patients with osteoarthritis (21.23+/-3.11 micromol H2O2 Equiv./L) than in healthy subjects (14.19+/-3.16 micromol H2O2 Equiv./L, P<0.001) and the results showed a significant negative correlation with total antioxidant capacity (TAC) (r=-0.66 P<0.01).

CONCLUSIONS

This easy, stable, reliable, sensitive, inexpensive and fully automated method that is described can be used to measure total oxidant status.

Development of a novel and automated fluorescent immunoassay for the analysis of beta-lactam antibiotics

An automated immunosensor for the rapid and sensitive analysis of penicillin type beta-lactam antibiotics has been developed and optimized. An immunogen was prepared by coupling the common structure of the penicillanic beta-lactam antibiotics, i.e., 6-aminopenicillanic acid to keyhole limpet hemocyanin. Polyclonal antibodies raised in rabbits after immunization with this conjugate have been applied for the development of a competitive fluoroimmunoassay (FIA), using a novel fluorescent penicillin {[2S,5R,6R]-3,3-dimethyl-7-oxo-6-[(pyren-1ylacetyl)amino]-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxilic acid, PAAP} as the tracer and penicillin G as the reference antibiotic. Protein A/G covalently bound to an azlactone-activated polymeric support was used for the orientated capture of the antibody-antigen immunocomplexes. Upon desorption from the immunosupport, the emission signal generated by the PAAP-Ab complexes is related to the antibiotic concentration in the sample. The 50% binding inhibition concentration of penicillin G standard curves was at 30 ng mL(-)(1) with a detection limit (10% binding inhibition) of 2.4 ng mL(-)(1) and a dynamic range from 6.0 to 191 ng mL(-)(1) (20-80% binding inhibition) penicillin G. The generic nature of the antiserum was shown by good relative cross-reactivities with penicillin type beta-lactam antibiotics such as amoxicillin (50%), ampicillin (47%), and penicillin V (145%) and a lower response to the isoxazolyl penicillins such as oxacillin, cloxacillin, and dicloxacillin. No cross-reactivity was obtained for cephalosporin type beta-lactam antibiotics (cephapirin), cloramphenicol, or fluoroquinolones (enrofloxacin and ciprofloxacin). The total analysis time was 23 min per determination, and the immunoreactor could be reused for more than 200 cycles without significant loss of activity. The immunosensor has been successfully applied to the direct analysis of penicillin G and amoxicillin in spiked influent and effluent sewage treatment plant water samples with excellent recoveries (mean values for penicillin G and amoxicillin, 99 and 105%, respectively). Results displayed by comparative analysis of the immunosensor with a chromatographic procedure for penicillins showed excellent agreement between both methods.

Platelets in the paediatric population: the influence of age and the limitations of automation

Accurate and precise platelet counting is important for the clinical management of children with platelet disorders. Current automated technologies are often unable to discriminate platelets from non-platelet particles particularly in circumstances where platelet anisocytosis is common. This study compares manual methodology and the automated technologies; impedance, optical density and CD61 immunoplatelet method (available on the Cell Dyn 4000) with the reference method of flow cytometric analysis in a paediatric population. A total of 141 samples were analysed and divided into specific age related groups and groups with thrombocytopenia and thrombocytosis. Data analysis showed that the CD61 method compared best with the reference method and this was evident in all the specified groups. The mean platelet count obtained by optical and manual methods were lower, suggesting that these methods are less reliable. The impedance count method was accurate despite its limitations. Strong correlations were observed in the 2-14 year age group but there was greater variation in the <1 month group supporting the theory that there is a greater variation in platelet characteristics in neonates. The CD61 method is the automated method of choice and would be particularly useful in the problem groups (platelet counts <50 x 10(9)/l and neonates <1 month old).

Analysis and enumeration of T cells, B cells and NK cells using the monoclonal antibody fluorescence capability of a routine haematology analyser (Cell-Dyn CD4000)

This communication details a method for the quantitative and qualitative analysis of blood T-, B- and NK-cell populations using the Abbott Cell-Dyn CD4000 haematology analyser. A series of 66 ethylenediaminetetraacetic acid (EDTA)-anticoagulated samples with lymphocyte counts between 0.2 and 33.3 x 10(9)/l were selected and analysed with CD3, CD19, Ia and CD56 monoclonal reagents. The flow cytometry reference method utilized a lymphocyte gate defined by optical scatter, with phenotypic analyses referencing to this gate and the absolute lymphocyte count. The CD4000 method analysed all leucocyte events, set primary gates for specific immunophenotypic fractions, and then determined population counts by reference to the white blood cell (WBC) count. Comparisons of CD3+ T-cell and CD19+ B-cell numbers showed high coefficients of correlation (R(2) > 0.95) and agreement (y = 1.01x) between the CD4000 and flow cytometry reference methods. Lower coefficients of correlation were obtained for CD3-CD56+ (R(2) = 0.52) and CD3+CD56+ (R(2) = 0.83) components. No major discrepancies were observed, and the CD4000 procedures additionally provided qualitative insights into the possibility of T-cell activation. The potential to undertake immediate analysis of EDTA-anticoagulated blood samples to determine the nature of abnormal lymphocyte morphology or numbers represents a considerable advance in the capability of haematology laboratories.

Correlation of same-visit HbA1c test with laboratory-based measurements: a MetroNet study

BACKGROUND

Glycated hemoglobin (HbA1c) results vary by analytical method. Use of same-visit HbA1c testing methodology holds the promise of more efficient patient care, and improved diabetes management. Our objective was to test the feasibility of introducing a same-visit HbA1c methodology into busy family practice centers (FPC) and to calculate the correlation between the same-visit HbA1c test and the laboratory method that the clinical site was currently using for HbA1c testing.

METHODS

Consecutive diabetic patients 18 years of age and older having blood samples drawn for routine laboratory analysis of HbA1c were asked to provide a capillary blood sample for same-visit testing with the BIO-RAD Micromat II. We compared the results of the same-visit test to three different laboratory methods (one FPC used two different laboratories).

RESULTS

147 paired samples were available for analysis (73 from one FPC; 74 from the other). The Pearson correlation of Micromat II and ion-exchange HPLC was 0.713 (p < 0.001). The Micromat II mean HbA1c was 6.91%, which was lower than the 7.23% from the ion-exchange HPLC analysis (p < 0.001). The correlation of Micromat II with boronate-affinity HPLC was 0.773 (p < 0.001); Micromat II mean HbA1c 6.44%, boronate-affinity HPLC mean 7.71% (p < 0.001). Correlation coefficient for Micromat II and immuno-turbidimetric analysis was 0.927 (p < 0.001); Micromat II mean HbA1c was 7.15% and mean HbA1c from the immuno-turbidimetric analysis was 7.99% (p = 0.002). Medical staff found the same-visit measurement difficult to perform due to the amount of dedicated time required for the test.

CONCLUSION

For each of the laboratory methods, the correlation coefficient was lower than the 0.96 reported by the manufacturer. This might be due to variability introduced by the multiple users of the Micromat II machine. The mean HbA1c results were also consistently lower than those obtained from laboratory analysis. Additionally, the amount of dedicated time required to perform the assay may limit its usefulness in a busy clinical practice. Before introducing a same-visit HbA1c methodology, clinicians should compare the rapid results to their current method of analysis.

Automated on-line solid-phase extraction-liquid chromatography-electrospray tandem mass spectrometry method for the determination of ochratoxin A in wine and beer

An automated on-line solid-phase extraction-liquid chromatography-electrospray tandem mass spectrometry (SPE-LC-ESI-MS/MS) method was developed for the determination of ochratoxin A (OTA) in alcoholic beverages. Mean recoveries for wine and beer were, respectively, 75 and 82%. Detection was achieved in negative ionization with a Q TRAP mass spectrometer operating in multiple-reaction monitoring (MRM) mode or enhanced product ion (EPI) mode, using the third quadrupole as linear ion trap. The MRM mode turned out to be more sensitive; the method allowed accurate determination of OTA in the range of 0.01-25 ng mL(-1) using external calibration. Within-day and between-day relative standard deviation percentages were <6.2 and <9.1%, respectively. In EPI mode, fragmentation spectra at the limit of quantification (0.03 ng mL(-1)) and good linearity could be obtained. Application of the method (MRM mode) to the analysis of several wine and beer samples purchased in local stores revealed OTA levels in the ranges of 0.03-1.44 ng mL(-1) for wines and 0.02-0.14 ng mL(-1) for beers.

[Algorithm for automatic quantification of brain atrophy with computed tomography]

In this paper, a new, fully-automatic method for the quantification of brain atrophy based on CT volume data is put forward by taking advantage of the characteristics of cerebral CT images in combination with the prior medical knowledge. This algorithm has been verified through the calculation of 2388 cases of normal and brain atrophy subjects.

Rapid, fully automated flow injection antioxidant capacity assay

A flow injection method for antioxidant capacity assessment based on a low-cost laboratory-made analyzer is reported. A sample of 30 microL is injected in acetate buffer stream, pH 4.6, that converges with ABTS*(+) reagent stream. Detection is achieved by monitoring absorbance at 414 nm. The proposed method achieves a sample throughput of up to 120 samples h(-1), the detection limit being 1.3 microM trolox. Precision was better than 5% relative standard deviation (n = 4) and the linear range was 4-100 microM, expanded to 250 microM trolox utilizing concentration gradients formed along the injected sample bolus. Information on reaction kinetics is obtained through a single injection. The method was applied to pure compounds and wine and honey samples. Good correlation was found between antioxidant capacity assessed through the proposed method and phenolic content: r = 0.94 for red wines, r = 0.96 for white and rose wines, and r = 0.89 for honeys.

Analysis of zearalenone in cereal and Swine feed samples using an automated flow-through immunosensor

The development of a sensitive flow-though immunosensor for the analysis of the mycotoxin zearalenone in cereal samples is described. The sensor was completely automated and was based on a direct competitive immunosorbent assay and fluorescence detection. The mycotoxin competes with a horseradish-peroxidase-labeled derivative for the binding sites of a rabbit polyclonal antibody. Control pore glass covalently bound to Prot A was used for the oriented immobilization of the antibody-antigen immunocomplexes. The immunosensor shows an IC(50) value of 0.087 ng mL(-1) (RSD = 2.8%, n = 6) and a dynamic range from 0.019 to 0.422 ng mL(-1). The limit of detection (90% of blank signal) of 0.007 ng mL(-1) (RSD = 3.9%, n = 3) is lower than previously published methods. Corn, wheat, and swine feed samples have been analyzed with the device after extraction of the analyte using accelerated solvent extraction (ASE). The immunosensor has been validated using a corn certificate reference material and HPLC with fluorescence detection.

Determination of urinary nucleosides by direct injection and coupled-column high-performance liquid chromatography

A coupled-column liquid chromatographic method for the direct analysis of 14 urinary nucleosides is described. Efficient on-line clean-up and concentration of 14 nucleosides from urine samples were obtained by using a boronic acid-substituted silica column (40 mm x 4.0 mm I.D.) as the first column (Col-1) and a Hypersil ODS2 column (250 mm x 4.6 mm I.D.) as the second column (Col-2). The mobile phases applied consisted of 0.25 mol/L ammonium acetate (pH 8.5) on Col-1, and of 25 mmol/L potassium dihydrogen phosphate (pH 4.5) on Col-2, respectively. Determination of urinary nucleosides was performed on Col-2 column by using a linear gradient elution comprising 25 mmol/L potassium dihydrogen phosphate (pH 4.5) and methanol-water (60:40, v/v) with UV detection at 260 nm. Urinary nucleosides analysis can be carried out by this procedure in 50 min requiring only pH adjustment and the protein precipitation by centrifugation of urine samples. Calibration plots of 14 standard nucleosides showed excellent linearity (r > 0.995) and the limits of detection were at micromolar levels. Both of intra- and inter-day precisions of the method were better than 6.6% for direct determination of 14 nucleosides. The validated method was applied to quantify 14 nucleosides in 20 normal urines to establish reference ranges.

Immunocytometric quantitation of foeto-maternal haemorrhage with the Abbott Cell-Dyn CD4000 haematology analyser

This study evaluated the extended use of a haematology analyser (Abbott Cell-Dyn CD4000) for the immunofluorescent enumeration of foeto-maternal haemorrhage (FMH) with fluorescein isothiocyanate-labelled monoclonal anti-RhD. Method performance was assessed with artificial FMH standards, and a series of 44 clinical samples. Within run precision was <15% (coefficient of variation, CV) for FMH volumes of 3 ml and above, 18.8% at an FMH volume of 2 ml and 31.7% at an FMH volume of 1 ml. Linearity analysis showed excellent agreement (observed FMH% = 0.98x expected FMH% + 0.02), and a close relationship (R(2) = 0.99) between observed and expected FMH percentages. The lower limit of quantification of the CD4000 (SRP-Ret) method with a maximum CV of 15% was 1.6 ml, and the limit of detection was <1 ml. Parallel Kleihauer-Betke test (KBT) assessments of FMH standards showed an overall trend for higher KBT values (observed = 1.25x expected - 0.38). At an FMH level of 4 ml, KBT observer estimates ranged from 0.57 to 11.94 ml with a mean inter-observer CV of 63%. For 44 clinical samples, there was decision point agreement between KBT and SRP-Ret results for 42 samples with an FMH of <2 ml. Analysis in the low FMH range (<1 ml) showed that small volume foetal leaks could be detected with the SRP-Ret method in most of 23 samples with negative KBT results. CD4000 SRP-Ret method performance for FMH determination was similar to that reported for flow cytometry.

An automated spectrophotometric method for measuring canine ceruloplasmin in serum

An automated method for the determination of ceruloplasmin activity was developed and validated in canine serum. The method is based on the in vitro oxidase activity that this protein shows with substances such as p-phenylenediamine. In order to determine optimum assay conditions, the effects of the substrate concentration, buffer pH, reaction time and EDTA on the reaction were evaluated. The precision of the assay was good with within-run and between-run coefficients of variation lower than 10%. The method measured the ceruloplasmin values in a proportional and linear manner (r = 0.99) with a limit of detection of 0.0007 +/- 0.0001 Delta Abs/min. A temperature of -20 degrees C kept the reagent stable for 30 days. The method is cheap and easy to adapt to any automated biochemical analyser, considerably decreasing the processing time required with the manual method. Additionally it allows to differentiate dogs with pyometra and trauma from clinically healthy dogs.

Stability of suspensions, emulsions, and foams studied by a novel automated analyzer

The stability of dilute and concentrated dispersions (suspensions, emulsions, and foams) has been studied by a newly developed automated dispersion stability analyzer, DiStA 24. The analyzer operates by taking consecutive images of the samples studied and analyzing them by a personal computer (PC). As a result, the vertical profile of light scattered from each sample is obtained, recorded, and analyzed at time intervals preset by the computer software. In this way, the destructive processes in dispersions (sedimentation, creaming, and coalescence) can be detected well before it is possible by the naked eye and monitored automatically in the temperature range 0-50 degrees C. The new analyzer differs from the existing instruments by its simplicity and high productivity, allowing 24 samples to be measured simultaneously.

Automated sperm morphometry and morphology analysis of canine semen by the Hamilton-Thorne analyser

Computer-assisted sperm morphometry has the potential to eliminate several drawbacks inherent to the current methods of sperm morphology evaluation, and allows for the identification of subtle sperm characteristics which cannot be detected by visual evaluation. In the present study, the Metrix Oval Head Morphology software implemented in the Hamilton-Thorne CEROS (version 12.1; HTR 12.1 Metrix) computer-aided semen analyser was evaluated for canine sperm morphometry and morphology analysis. Comparison of sperm morphometric measurements of 200 spermatozoa from pooled semen samples (n = 4) at 40x and 60x demonstrated a more accurate identification of the sperm head boundaries at a magnification level 60x. Dilution of pooled semen samples (n = 4) to a sperm concentration of 50 x 10(6) ml(-1) allowed for a correct evaluation of the sperm cell dimensions whereas 100 x 10(6) and 200 x 10(6) ml(-1) resulted in a higher percentage of rejected spermatozoa due to overlapping. No differences in morphometric dimensions were found when 100 or 200 spermatozoa were evaluated for each of 15 dogs. The mean morphometric parameters of canine spermatozoa, based on the fresh ejaculates of 23 dogs, were: major 6.65 +/- 0.20 microm; minor 3.88 +/- 0.14 microm; area 20.66 +/- 1.04 microm2; elongation 58.64 +/- 2.58 %; perimeter 17.57 +/- 0.43 microm and tail length 48.93 +/- 10.16 microm. Large variations in morphometric dimensions were detected among individual dogs. After cryopreservation, significantly lower morphometric dimensions were obtained for all the evaluated sperm samples (n = 12). Finally, a correlation of 0.82 (P < 0.05) was established for the percentage of normal spermatozoa assessed by subjective evaluation and by the HTR 12.1 Metrix (n = 39 semen samples). In conclusion, dilution of the semen samples to approximately 50 x 10(6) spermatozoa/ml and an objective lens magnification of 60x, analysing at least 100 spermatozoa, are the technical settings proposed to obtain reliable and objective sperm morphometric measurements by the HTR 12.1 Metrix in canine.

Evaluation of the coulter LH 750 haematology analyzer compared with flow cytometry as the reference method for WBC, platelet and nucleated RBC count

The Coulter LH 750 is a new haematology analyser with several new features: a count of nucleated red blood cells (NRBCs), automated WBC correction in presence of a flag indicating a cellular interference and a lower incidence of platelet or WBC interference flags when compared with the GEN.S, our current instrument. We had three main goals in our study: evaluating the LH 750 WBC counts when a GEN.S flag suggests a risk of WBC interference, ascertaining whether the platelet counts not flagged by the LH 750 were accurately assessed in samples flagged by the GEN.S and evaluating the NRBC assay provided by the LH 750. Flow cytometry, using CD45 and CD41, respectively for WBC and platelet labelling, was used as a reference method to assess the accuracy of the LH 750 counts. NRBC were identified by double labelling with propidium iodide (PI) and CD45, NRBCs being CD45-/PI+. A significant relationship was found between LH 750 and flow cytometric WBC counts, whether a WBC correction was made by the LH 750 (r = 0.9809, n = 54) or not (r = 0.9901, n = 23). A highly significant relationship was observed for platelets not only in the range from 0 to 450 x 10(9)/l (r = 0.981, n = 108) but also in cases of thrombocytopenia (range: 0-80 x 10(9)/l; r = 0.956, n = 51). In samples with NRBCs, the NRBC percentages given by the LH 750 and by flow cytometry were highly correlated (r = 0.977, n = 60) and WBC counts were accurate. In conclusion, the reduction in flagging by the LH 750, the accuracy of the results, and the availability of a NRBC count, constitute major advantages.

Differential leukocyte counts determined in chicken blood using the Cell-Dyn 3500

BACKGROUND

Automated hematology instruments commonly are used for mammalian blood analysis, but there is a lack of accurate automated methods available for avian leukocyte analysis.

OBJECTIVE

The aim of this study was to validate differential leukocyte counts in blood from chickens using the Cell-Dyn 3500 hematology system and avian-specific software.

METHODS

Blood samples were collected in lithium-heparin tubes from 2 groups (n = 84 and n = 139) of laying hens. Manual 200-cell differential counts were done on routinely-stained blood smears, and manual total granulocyte counts (heterophils and eosinophils) were done using an eosinophil stain in a counting chamber. Automated differential counts were done using VET 2.3, a research and development version of avian-specific software for the Cell-Dyn 3500. Results were analyzed using Pearson's correlation and difference plots.

RESULTS

Automated granulocyte counts from the Cell-Dyn were in good agreement with manual granulocyte counts (r = 0.93 and 0.80 for the 2 study groups). No correlation was found between automated and manual lymphocyte counts. Correlation coefficients for monocyte counts were 0.70 and 0.43.

CONCLUSION

Automated leukocyte results from the Cell-Dyn using VET 2.3 software were not fully accurate. Total granulocyte counts may be of clinical usefulness, but results obtained for other parameters were unreliable.

An Evaluation of the Utility of Performing Body Fluid Counts on the Coulter LH 750

Performing a manual body fluid count is a tedious, time-consuming, and frequently imprecise process for any clinical laboratory. The ability to perform many of these counts with an automated hematology analyzer has the real potential of making a major impact on laboratory precision and productivity. The manual chamber count is fraught with many variables and is often very technologist/technique dependent, often leading to inaccuracies in test results. Our laboratory undertook a series of studies designed to evaluate the capability of the Coulter LH 750 hematology analyzer to supplement our current manual method in the performance of body fluid analysis. First, we established the performance of our current manual counting method, the gold standard against which LH 750 performance would be judged. We looked at the precision of manual cell counting by having 4 technologists perform manual counts on each of 35 spinal, synovial, peritoneal, and other fluids with white blood cell (WBC) and/or red blood cell (RBC) counts of greater than 0.3 x 10(9) /L and 0.03 x 10(12) /L, respectively. Our results support earlier reports that the variability in counts among technologists using the manual chamber cell count methods is often very significant. After each sample was manually counted, it was analyzed on the Coulter LH 750, and the results were compared with those of our current manual method. Results showed good correlation between the manual and LH 750 methods. Next, we conducted a series of separate tests to evaluate the stability of different cellular elements (WBCs and RBCs) in each of these body fluid types. The study consisted of 2 sets of 4--3-mL samples of each fluid type--which were analyzed on the LH 750 immediately on receipt and after 1 hour, 4 hours, 8 hours, 16 hours, and 24 hours. The findings suggested varying degrees of stability that were dependent on fluid type and initial cell concentration. Finally, we looked at whether it is necessary to perform background counts before analyzing each body fluid sample and the impact of automating body fluid counts on our workload.

Inaccuracy of routine creatinine measurement in canine urine

BACKGROUND

Urine creatinine concentration often is used in ratios such as urine protein:creatinine to compensate for dilution or concentration of spot urine samples.

OBJECTIVE

The purpose of this study was to compare the accuracy of different techniques of urine creatinine measurement currently available for veterinary practitioners.

METHODS

In 104 samples of canine urine diluted 1:20 with distilled water, creatinine concentration was measured using a kinetic Jaffé reaction assay, and an enzymatic technique on an automatic analyzer (Elimat) and 3 benchtop analyzers (Reflovet, Scil; Vitros DT2, Ortho-Clinical Diagnostics; Vettest 8008, IDEXX) used in veterinary practice.

RESULTS

The Jaffé and enzymatic techniques on the Elimat were not significantly different, and their inaccuracy tested with human control urines was <5%. The benchtop analyzers underestimated creatinine concentration, especially at concentrations >2000 mg/L. Inaccuracy was higher with multilayer slide technology systems (Vitros and Vettest) than with the Reflovet system. Results were approximately 25% and 2% lower, respectively, than with the Elimat at urine creatinine concentrations about 2000 mg/L.

CONCLUSION

Inaccuracy in urine creatinine measurements using benchtop analyzers should be taken into account when defining decision thresholds, which should be corrected according to the method used to avoid misinterpretations.

Comparison between the enzymatic vitros assay for creatinine determination and three other methods adapted on the Olympus analyzer

To evaluate the relationship between the enzymatic Vitros assay for creatinine determination and other methods, we determined creatinine concentration in 400 heparin samples. Plasma creatinine level was successively determined on the Vitros 750 analyzer (Johnson & Johnson Co., Rochester, NY) and on the Olympus AU2700 analyzer (Olympus France, Rungis, France), using three reagents in the same assay: Olympus-Jaffé and two enzymatic commercial kits-Crea Plus (Roche Diagnostics, Meylan, France) and Enzymatic Creatinine (Randox, Mauguio, France). Comparison of Jaffé and enzymatic measurements of plasma creatinine levels revealed a high correlation when considering all values ranged from 20-1000 micromol/l (r > 0.99). However, for values <60 micromol/l, enzymatic reagents provided best results. Enzymatic methodology is a better clinical choice for the accurate measurement of creatinine, especially for neonates, pediatrics, and hematology units. Because analytical performance and the costs of Randox creatinine were satisfactory for our laboratory, this method, adapted on the Olympus analyzer, was chosen for routine determination of creatinine levels. According to the Valtec protocol (8), no interferences such as hemolysis, lipemia, or bilirubin were detected for Enzymatic Creatinine Randox.

Evaluation of an Automated Instrument for Viability and Concentration Measurements of Cryopreserved Hematopoietic Cells

Two important parameters for determination of deleterious effects of cellular processing on hematopoietic progenitor cells are cell viability and concentration. The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins Hospital evaluated the Beckman Coulter Vi-Cell automated instrument for the measurement of these two parameters. Using 33 thawed hematopoietic progenitor cell samples, automated Vi-Cell viability results were compared to those obtained using the standard trypan blue manual method. In addition, cell concentrations from these samples were compared with results from the Model Z2 Coulter Counter. Chinese Hamster Ovary cells were used for the evaluation of Vi-Cell linearity at the Beckman Coulter Cellular Analysis Development Center. Significant correlation was obtained when the two methods were compared for both cell concentration and percentage viability (P < .0001). The results of the linearity study indicated that the Vi-Cell is linear from approximately 5 x 10(4) to greater than 1 x 10(7) cells/mL. The Vi-Cell uses sample volumes as low as 0.5 mL; cell diameters may be 2 to 70 microns. The Vi-Cell automated instrument offers many significant advantages for cell analyses in today's busy laboratory environment.

Flow Cytometric Validation of Automated Differentials in Pediatric Patients

Manual differential white blood cell (WBC) counting has been considered the gold standard and is routinely used to validate differentials obtained with other methodologies. To validate the accuracy of automated lymphocyte counts, we compared 2-part differentials using a Coulter HmX hematology analyzer and a Coulter XL flow cytometer to analyze 57 pediatric samples with WBC counts ranging from 0.7 k to 33.4 k. These data were compared with manual differential counts. We found excellent correlation between the two automated lymphocyte and monocyte counting methods that surpassed the manual correlations, indicating manual lymphocyte or monocyte counts are unnecessary in the setting of quality scatterplots. To evaluate the use of automated differentials for our most labor-intensive cases (low WBCs, which frequently require manual differentials) we then compared 3-part differentials using the HmX hematology analyzer and flow cytometer for 51 samples with total WBC < or = 1.1 x 10(9)/L. Manual differentials (< or = 100-cell counts) were available on 27 samples. Although the correlations for manual versus automated or flow differentials were good for all cell types, the correlation between the two automated methods was better, irrespective of the hematology analyzer scatterplot quality. Preliminary data provide additional evidence that automated differentials in samples with WBC of < or = 1.1 x 10(9)/L are acceptable for reporting, thus saving technologist time and improving patient care by decreasing the resulting turnaround time. These studies suggest that comparison with a standardized procedure like flow cytometry would be a better method for validation of automated differentials than comparison with the less precise, more laborious manual differential.

Comparative evaluation of schistocyte counting by an automated method and by microscopic determination

Schistocytes are circulating RBC fragments. The morphologic identification of schistocytes is difficult because the shapes to which they correspond are still under discussion. Automated hematology systems permit the possibility of direct measurement of RBC fragments. We compared schistocyte counts performed by different biologists and technicians with the automated counts by the ADVIA 120 (Bayer Health Care, Tarrytown, NY). The agreement between the ADVIA 120 and the average of the observers gives a correlation coefficient of 0.7274 (95% confidence interval, 0.6285-0.8019). The ADVIA 120 has a tendency to overestimate the count (average, +0.445%). No false-negative case was recorded. The maximum sensitivity (detection of 100% of samples with schistocytes) of the analyzer was determined at a threshold value of 0.25%, but the specificity was low (20%). Therefore, a blood smear examination remains necessary to confirm schistocyte presence. However, the clinical features correlated particularly with negative automated RBC fragments, and the high negative predictive value of RBC fragments ruled out thrombotic events (macroangiopathies or microangiopathies).

On-line monitoring of a two-stage anaerobic digestion process using a BOD analyzer

A computer-controlled biochemical oxygen demand (BOD) analyzer has been developed for fast estimation of biochemical oxygen demand (BODst) automatically with the purpose of on-line monitoring of a process for conversion of biomass under field conditions. The instrument was tested by on-line monitoring of the connecting stream between two stages of a two-stage anaerobic process in laboratory scale. In the first stage, hydrolysis of sugar beet leaves and its conversion into volatile fatty acids and other low molecular weight substrates took place. The effluent from the first reactor was used as a feed stream to the second stage, i.e. an anaerobic contact reactor. The feed stream was sampled intermittently, diluted and analyzed by the BOD analyzer automatically in order to estimate the organic loading rate to the reactor. The results from this study demonstrated that the BOD analyzer could be a stand-alone and promising sensor device for rapid on-line monitoring of easily biodegradable organic substances in biological treatment processes.

Diagnostic performance of the variant lymphocyte flag of the Abbott Cell-Dyn 4000 haematology analyser

BACKGROUND

In addition to differential cell counts, modern haematology analysers generate suspect flags if abnormal cells are detected. Reports on validation of suspect flags are scarce. We have routine experience with the Abbott Cell-Dyn 4000 analyser for over 5 years and have previously demonstrated the utility of the blast flag. Here we report a similar study on the performance of the analyser's Variant Lymphocyte (VL) flag.

AIM OF THE STUDY

Evaluation of the diagnostic performance of the Cell-Dyn 4000 VL flag, as compared with lymphocyte morphology in blood smears. In addition, we investigated the usefulness of the numerical VL flag confidence index as provided by the analyser.

MATERIALS AND METHODS

All samples generating a VL flag were reviewed over a 5-month period. We also reviewed smears from patients with known lymphoid disorders, even if the analyser did not flag the sample. Two experienced investigators assessed lymphocyte morphology independently.

RESULTS

In total, 187 samples were included in the study, of which 183 had a VL flag and four had not. Of the 183 flagged samples, 83 appeared to have abnormal lymphocyte morphology and 100, normal lymphocyte morphology. The sensitivity of the VL flag for detecting abnormal lymphocytes was 0.95 and the positive predictive value was 0.44. Using ROC analysis of the VL flag confidence index, the area under the ROC curve was 0.58 (95% confidence interval 0.50-0.65).

CONCLUSIONS

The Cell-Dyn VL flag has reasonable sensitivity but a high false-positive rate. In addition, its performance is insufficient for detecting clinically relevant abnormal lymphocytes. As the VL flag appeared to rely mainly on numerical criteria, it has no added value over numerical criteria defined by the laboratory.

Performance characteristics of the IMMULITE 2000 erythropoietin assay

BACKGROUND

Erythropoietin (EPO) is a glycoprotein hormone produced by specialized cells in the kidney that acts as the primary regulator of erythropoiesis. Serum EPO measurements are useful for diagnostic evaluations of anemia and polycythemia.

METHODS

The IMMULITE 2000 is an automated random access immunoassay analyzer for the central laboratory. The limit of detection (LOD), linearity, imprecision, comparison to another commercially available assay, and reference interval of a new EPO assay for this analyzer were assessed.

RESULTS

The LOD was 0.2 U/l. The assay was linear within an allowable systematic error of 10% over the range tested (2-178 U/l). The total imprecision of the new assay was <7% for concentrations from 15.8 to 68.4 U/l. Comparison with the Advantage EPO assay method showed comparable results. Deming regression analysis gave a slope of 1.13+/-0.02, an intercept of -1.09+/-0.97, and a S(y/x) of 7.1 (r=0.99) over the range tested (2-200 U/l).

CONCLUSIONS

The IMMULITE 2000 EPO assay shows acceptable performance and is suitable for routine clinical use.

Direct analysis of pesticide residues in olive oil by on-line reversed phase liquid chromatography-gas chromatography using an automated through oven transfer adsorption desorption (TOTAD) interface

A fully automated on-line reversed phase liquid chromatography-gas chromatography system is described. The system uses a prototype of the automated through oven transfer adsorption desorption interface. The system is demonstrated by presenting a new rapid method for the determination of pesticide residue in olive oil, which is injected directly with no sample pretreatment step other than filtration. Methanol:water is used as the eluent in the LC preseparation step, while the LC fraction containing the pesticide is automatically transferred to the gas chromatograph. Detection limits of pesticides varied from 0.18 to 0.44 mg/L when a flame ionization detector was used. As an example, relative standard deviation and linear calibration are presented for terbutryne.

Testosterone measured by 10 immunoassays and by isotope-dilution gas chromatography-mass spectrometry in sera from 116 men, women, and children

BACKGROUND

Commercially available testosterone immunoassays give divergent results, especially at the low concentrations seen in women. We compared immunoassays and a nonimmunochemical method that could quantify low testosterone concentrations.

METHODS

We measured serum testosterone in 50 men, 55 women, and 11 children with use of eight nonisotopic immunoassays, two isotopic immunoassays, and isotope-dilution gas chromatography-mass spectrometry (ID/GC-MS).

RESULTS

Compared with ID/GC-MS, 7 of the 10 immunoassays tested overestimated testosterone concentrations in samples from women; mean immunoassay results were 46% above those obtained by ID/GC-MS. The immunoassays underestimated testosterone concentrations in samples from men, giving mean results 12% below those obtained by ID/GC-MS. In women, at concentrations of 0.6-7.2 nmol/L, 3 of the 10 immunoassays gave positive mean differences >2.0 nmol/L (range, -0.7 to 3.3 nmol/L) compared with ID/GC-MS; in men at concentrations of 8.2-58 nmol/L, 3 of the 10 immunoassays tested gave mean differences >4.0 nmol/L (range, -4.8 to 2.6 nmol/L).

CONCLUSION

None of the immunoassays tested was sufficiently reliable for the investigation of sera from children and women, in whom very low (0.17 nmol/L) and low (<1.7 nmol/L) testosterone concentrations are expected.

[Dry chemistry method for measuring serum urea and creatinine]

OBJECTIVE

To evaluate the dry chemistry method for measuring serum urea and creatinine.

METHODS

Urea and Creatinine were measured by dry and wet chemistry methods respectively. The results and the relativity between the two methods were compared.

RESULTS

The correlative factors were 0.996 and 0.995, respectively, implying fairly good comparability. The precision of the dry chemistry method was good, with the coefficient variation (CV) below 5%. With favorable accuracy, the recovery rate were 106.7% and 107.2%, respectively.

CONCLUSION

Dry chemistry method is rapid and accurate for emergent testing of serum urea and creatinine.

Rapid method development for chiral separation in drug discovery using sample pooling and supercritical fluid chromatography-mass spectrometry

A novel strategy for rapid chiral method development has been implemented using sample pooling and supercritical fluid chromatography-mass spectrometry (SFC-MS) on four chiral stationary phases, namely Chiralpak AD and AS, and Chiralcel OJ and OD, and eight different modifier concentrations (5 to 40% methanol-0.2% isopropylamine). The screening is performed under an outlet pressure of 110 bar at 35 degrees C, and at a flow-rate of 2.5 ml/min for the initial 20 min and then ramped up to 4 ml/min and held for 4.5 min to elute all solutes from the column. The entire process is fully automated from injection to data processing, and operates unattended for 15 h overnight to obtain optimal chiral separation for multiple compounds. A unique feature of using SFC-MS to monitor chiral synthesis is the negligible interferences from achiral impurities. In addition, with SFC-MS, enantiomeric excess can be determined with much lower detection limits than UV and much shorter analysis times compared to normal-phase/reversed-phase liquid chromatography.

Liquid chromatographic determination of natural and synthetic colorants in lyophilized foods using an automatic solid-phase extraction system

Five synthetic and five natural colorants were determined in lyophilized dairy products and fatty foods using an automatic method based on lixiviation and a solid-phase extraction process that includes cotton and RP-C(18) columns for the sequential retention of synthetic colorants and natural colorants, respectively. The lyophilization of the sample coupled with the separation procedure provides clean extracts despite the complexity of the matrices studied. In addition, the lyophilization process preserves the sample for at least 2 months without changes in the concentrations of the colorants. Identification and determination of synthetic and natural colorants were carried out using a liquid chromatograph equipped with a diode array detector. The detection limits achieved for all of the colorants (0.03-75 microg/g of lyophilized sample) allowed their determination within the limits established by the European Union, with good precision (approximately 4.5%). In addition, colorants spiked to different foods provided average recoveries (spiked at three concentration levels in four types of dairy samples and in three types of fatty foods) near 94 +/- 4%.

Comparison of red blood cell volume distribution curves and phase-contrast microscopy in localization of the origin of hematuria

OBJECTIVES

To determine the ability, reliability, and accuracy of urinary red blood cell volume distribution curves obtained with the use of an autoanalyzer to identify the origin of isolated microscopic hematuria and compare the results with those obtained with phase-contrast microscopy (PCM).

METHODS

A prospective evaluation was performed in 45 patients with glomerular or nonglomerular microhematuria detected by urinalysis, PCM, radiologic evaluation, endoscopy, and, sometimes, renal biopsy. Urine samples were analyzed in an electronic particle-size analyzer, and the tests were repeated to assess reliability. The kappa correlation coefficient was used to assess reliability and to compare the results with the final diagnosis and with those obtained with PCM.

RESULTS

Of the 28 patients who had a single definite cause of hematuria, 16 had glomerular bleeding and 12 nonglomerular bleeding. The origin of hematuria was correctly identified by the autoanalyzer in 60.7% of cases. A statistically significant correlation was found with the final diagnosis (kappa = 0.433, P = 0.048). The reliability was excellent (kappa = 0.917, P <0.0001). Of 16 patients with glomerulonephritis, 10 (62.5%) were correctly identified by PCM and 14 (87.5%) by the autoanalyzer. In 12 patients with nonglomerular bleeding, PCM was accurate in 7 (58%) and the autoanalyzer in 3 (25%). The results were statistically correlated with the findings of PCM (kappa = 0.327, P <0.00001).

CONCLUSIONS

The use of an autoanalyzer is easy, reproducible, and noninvasive. It provides reliable information to orient the diagnosis toward glomerular or nonglomerular bleeding. It is as accurate as PCM for screening for the source of hematuria.

A microcapillary trap cartridge-microcapillary high-performance liquid chromatography electrospray ionization emitter device capable of peptide tandem mass spectrometry at the attomole level on an ion trap mass spectrometer with automated routine operation

Reversed-phase microcapillary chromatography (RP-microLC) combined with electrospray ionization tandem mass spectrometry (ESI-MS/MS) is one of two prevailing techniques in proteomic analysis, the other being matrix-assisted laser desorption/ionization (MALDI). Despite the arguably better dynamic range obtainable with ESI, MALDI is increasingly popular due to ease of use, ruggedness and the ability to decouple separation from ionization. By contrast, in order to take advantage of the sensitivity and dynamic range afforded by the concentration-dependent nature of ESI, it is directly coupled to separations that take place in small i.d. RP-microLC columns. This gain in sensitivity often comes at a loss of ruggedness due to clogging of the small i.d. RP-microLC columns, one result of which is limited sample throughput. Here we describe a combined micropre-column-microLC-ESI device that is sensitive, rugged and modular in design allowing facile construction and troubleshooting. Due to low signal-to-noise as little as 1 attomole of a peptide can be selected by data-dependent methods for collision-induced dissociation. Importantly, the resulting tandem mass spectrum is of high enough quality to identify the peptide sequence by a database search against a complex database using SEQUEST. Finally, the device is demonstrated to be rugged as judged by >60 consecutive reversed-phase microLC separations on complex peptide mixtures before chromatographic resolution is degraded.

Automated determination of glucose-6-phosphate dehydrogenase (G6PD) on a SPOTCHECK Microflow analyzer

Glucose-6-phosphate dehydrogenase (G6PD) is the initial enzyme in the hexose monophosphate pathway of glucose metabolism. Deficiency of G6PD has been linked to increased sensitivity of red cells to hemolytic anemia due to certain oxidant drugs, infectious agents or fava beans. It is an inherited error in metabolism and has a high incidence in certain ethnic groups. Astoria-Pacific has developed an automated assay for use on the SPOTCHECK Microflow Analyzer for the semi-quantitative determination of G6PD activity in erythrocytes. After sample extraction, all assay steps are automated including reagent addition, incubation and data collection. Use of on-line dialysis removes interferences. The assay is intended primarily as a screening tool in the diagnosis and treatment of disease states associated with G6PD deficiency in newborns. G6PD in the dried blood spot is extracted and placed on the instrument. Samples are then aspirated into the system at a rate of 90 samples/hour. All other reagents are added by the SPOTCHECK Analyzer on-line during sample processing. Incubation of each sample occurs on-line at 37 degrees C, and after dialysis the NADPH reaction product is excited at 365 nm. Fluorescence is measured at 500 nm. A lack of fluorescence indicates a probable G6PD deficiency. Data reduction occurs real time through a FASPac software thus individual results are available during a run as soon as each sample analysis is complete. The Astoria-Pacific International G6PD reagent kit paired with the SPOTCHECK Microflow Analyzer provides an effective and easy to use screening tool for determining G6PD deficiency in newborns.

Performance characteristics of an automated high-sensitivity C-reactive protein assay on the Dimension RXL analyzer

BACKGROUND

C-reactive protein (CRP) is a nonspecific marker of inflammation that can be used as a marker for atherosclerotic risk. This application requires increased precision at low CRP concentrations compared to traditional assays.

METHODS

The Dimension RXL is an automated chemistry analyzer for central laboratory use. The limit of detection, limit of quantification, linearity and imprecision of a high-sensitivity CRP assay developed for it were assessed. Method comparison studies were performed using samples both inside and outside the reference interval. The presence of a prozone effect was also evaluated.

RESULTS

The limit of detection was 0.7 mg/l. The method was linear from 2 to 60 mg/l and from 1 to 60 mg/l using systematic error limits of 10% and 20%, respectively. The total imprecision was <10% for CRP concentrations above 1.5 mg/l. No prozone effect was seen at a CRP concentration of 450 mg/l, the highest concentration tested. Using samples from 212 apparently healthy adults, the Dimension RXL method demonstrated good concordance with the BN II high-sensitivity CRP method for samples in the highest quartile. It also compared well using samples with elevated CRP concentrations.

CONCLUSIONS

The Dimension RXL high-sensitivity CRP method may be adequate for atherosclerotic risk prediction in clinical practice if accurate and precise measurement is only required for the highest quartile. However, the total error of this method for CRP concentrations <3 mg/l appears too large for accurate assignment to lower risk groups.