Comparison of automated and rapid manual methods for the same-day identification of Enterobacteriaceae

The Vitek AMS automated instrument method for identification of Enterobacteriaceae was compared with two rapid manual methods intended for the same purpose, the Micro ID System and the API 20E Same-Day procedure, on a series of 400 consecutive fresh clinical isolates. Results were compared with identifications obtained using the API 20E System with overnight incubation and supplemental tube biochemicals (when needed). Both the final (8-hour) and a manually requested, presumptive 5-hour result from the AMS were compared with the 4-hour results provided by the Micro ID and the 5-hour results provided by the API. The Micro ID system proved to be the most rapid and accurate of the three test systems by correctly identifying 96.8% (387/400) of isolates. The API 20E using 5-hour readings identified 90.7% (363/400) of isolates, although 96.8% (387/400) could be identified if supplemental overnight tests were employed to separate profile codes with "good likelihood, but low selectivity." The AMS correctly identified 88.8% (355/400) isolates after 5 hours, and 95.0% (380/400) following 8 hours incubation.     

Comparison of automated and manual nucleic acid extraction methods for detection of enterovirus RNA

Automated nucleic acid extraction is an attractive alternative to labor-intensive manual methods. We compared two automated methods, the BioRobot M48 instrument (Qiagen, Inc.) and MagNA Pure (Roche Applied Sciences) methods, to two manual methods, the QIAamp Viral RNA Mini kit (Qiagen) and TRIzol (Invitrogen), for the extraction of enterovirus RNA. Analytical sensitivity was assessed by dilution analysis of poliovirus type 2 Sabin in cerebrospinal fluid. The sensitivity of PCR was equivalent after RNA extraction with QIAamp, BioRobot M48, and MagNA Pure. All 18 replicates of 100 PFU/ml were detected after extraction by the four methods. Fewer replicates of each successive dilution were detected after extraction by each method. At 10(-1) PFU/ml, 17 of 18 replicates were positive by QIAamp, 15 of 18 replicates were positive by BioRobot M48, and 12 of 18 replicates were positive by MagNA Pure; at 10(-2) PFU/ml, 4 of 17 replicates were positive by QIAamp, 2 of 18 replicates were positive by BioRobot M48, and 0 of 18 replicates were positive by MagNA Pure. At 10(-3) PFU/ml, no replicates were detected. Evaluation of TRIzol was discontinued after nine replicates due to a trend of lower sensitivity (at 10(-3) PFU/ml eight of nine replicates were positive at 100 PFU/ml, four of nine replicates were positive at 10(-1) PFU/ml, and zero of nine replicates were positive at 10(-2) PFU/ml). Concordant results were obtained in 24 of 28 clinical specimens after extraction by all methods. No evidence of contamination was observed after extraction by automated instruments. The data indicate that the sensitivity of enterovirus PCR is largely similar after extraction by QIAamp, BioRobot M48, and MagNA Pure; a trend of decreased sensitivity was observed after TRIzol extraction. However, the results of enterovirus PCR were largely concordant in patient samples, indicating that the four extraction methods are suitable for detection of enteroviruses in clinical specimens.     

PREPmate automated processor: comparison of automated and manual methods of liquid-based gynecologic sample preparation

The development of procedures for fully automated processing of liquid-based gynecologic samples has been the focus of considerable interest to the cytology laboratory. Liquid-based collection and processing technology has been shown to improve sample adequacy, resulting in an overall improvement in quality of sample preparations. PREPmate, an accessory to the PrepStain slide processor, automates the initial enrichment process of mixing and dispensing the specimen over a density gradient. This report describes a study evaluating cellularity and diagnostic reproducibility in SurePath samples processed using the PREPmate accessory compared to samples processed using a manual technique. Samples processed using the PREPmate accessory contained 8.3% more squamous cells. Exact diagnostic reproducibility between preparation types was 83.3%; when considering negative vs. abnormal (ASCUS+), in adequate samples, reproducibility was 100%.     

Comparison of the quality of temporal subtraction images obtained with manual and automated methods of digital chest radiography

The authors have been developing a fully automated temporal subtraction scheme to assist radiologists in the detection of interval changes in digital chest radiographs. The temporal subtraction image is obtained by subtraction of a previous image from a current image. The authors' automated method includes not only image shift and rotation techniques but also a nonlinear geometric warping technique for reduction of misregistration artifacts in the subtraction image. However, a manual subtraction method that can be carried out only with image shift and rotation has been employed as a common clinical technique in angiography, and it might be clinically acceptable for detection of interval changes on chest radiographs as well. Therefore, the authors applied both the manual and automated temporal subtraction techniques to 181 digital chest radiographs, and compared the quality of the subtraction images obtained with the two methods. The numbers of clinically acceptable subtraction images were 147 (81.2%) and 176 (97.2%) for the manual and automated subtraction methods, respectively. The image quality of 148 (81.8%) subtraction images was improved by use of the automated method in comparison with the subtraction images obtained with the manual method. These results indicate that the automated method with the nonlinear warping technique can significantly reduce misregistration artifacts in comparison with the manual method. Therefore, the authors believe that the automated subtraction method is more useful for the detection of interval changes in digital chest radiographs.     

Evaluation of the Yellow IRIS. An automated method for urinalysis

The authors evaluated the Yellow IRIS automated urinalysis instrument (International Remote Imaging Systems, Chatsworth, CA 91311) in terms of its analytic performance as well as its ease of use. The Yellow IRIS is a system using automated intelligence microscopy (AIM), coupled with a dipstick reader and specific gravity module. The instrument can handle up to 30 specimens per hour in the authors' setting as compared with 10 specimens per hour using a full manual urinalysis coupled with microscopic examination. The authors conclude that the Yellow IRIS performed better than the manual method in terms of precision, linearity, and throughput. In addition, the diagnostic yield using this system in terms of abnormal results was higher than would have been picked up by manual analysis alone.     

Comparison of two automated coagulometers and the manual tilt-tube method for the determination of prothrombin time

Two automatic coagulometers--ACL 810 (Instrumentation Laboratory), a laser-nephelometric centrifugal analyzer, and KoaguLab 40 A (Ortho Diagnostics), an optical automatic coagulometer--were compared with the manual tilt-tube method for the performance of prothrombin time (PT). Seven ISI- (International Sensitivity Index) calibrated commercial thromboplastin reagents were used for duplicate determinations in 30 normal subjects, 30 patients with liver disease, and 30 patients receiving stabilized oral anticoagulation. Clotting times were longer with the manual method than with ACL 810 and, to a lesser extent, with KoaguLab 40 A. Average imprecision of duplicate determinations (CV) was less than 1% with ACL 810; KoaguLab 40 A and the manual method had similarly higher imprecisions (2.8% and 2.7%). Differences in origin and slope of the regression curves of clotting times obtained with the coagulometers over the tilt-tube method were observed with all the reagents tested. Transformation of clotting times to PT ratios did not eliminate the bias resulting from the different clot-detection methods. A higher percentage of patients with liver disease had abnormal PT ratios when their plasma was tested with the coagulometers than with the manual method. Transformation of PT ratios to International Normalized Ratios effectively eliminated the bias resulting from the different thromboplastin reagents but had no effect on the bias resulting from the different clot-detection methods. A significant proportion of patients appeared excessively anticoagulated (INR greater than 4.5) with the coagulometers but not with the manual method. These results highlight the need for standardization of both instrumentations and reagents to improve monitoring of oral anticoagulant treatment.     

Comparison of evaluations for hormone receptors in breast carcinoma using two manual and three automated immunohistochemical assays

The aims of this study were to compare the quality of immunohistochemical assays of estrogen receptor (ER) and progesterone receptor (PR) and to compare the intermethod variability of assays from different manufacturers. immunohistochemical staining was entrusted to the following laboratories in Japan: Kyowa Medex, dealing with the products of BioGenex (Mishima, Shizuoka), DAKO Japan (Kyoto) and Ventana Japan (Yokohama). All slides were semiquantitatively evaluated according to the Allred score. Intermethod variability showed fair to moderate multirater kappa values for ER and PR (for total score, ER, kappa = 0.34; PR, kappa = 0.45). Another scoring system was also applied in which, irrespective of the intensity of nuclear staining, the proportion of cells stained in each specimen was recorded as 0; less than 1%; 1% or more and less than 10%; or 10% or more. Intermethod variability showed substantial multirater kappa values for ER and PR (according to percentage of positive cells, ER, kappa = 0.67; PR, kappa = 0.72). Concerning intermethod consistency, the scoring system based on the percentage of positive cells was advantageous over other scoring systems.     

Comparison of semi-automated image analysis and manual methods for tissue quantification in pancreatic carcinoma

Objective measurements of tissue area during histological examination of carcinoma can yield valuable prognostic information. However, such measurements are not made routinely because the current manual approach is time consuming and subject to large statistical sampling error. In this paper, a semi-automated image analysis method for measuring tissue area in histological samples is applied to the measurement of stromal tissue, cell cytoplasm and lumen in samples of pancreatic carcinoma and compared with the standard manual point counting method. Histological samples from 26 cases of pancreatic carcinoma were stained using the sirius red, light-green method. Images from each sample were captured using two magnifications. Image segmentation based on colour cluster analysis was used to subdivide each image into representative colours which were classified manually into one of three tissue components. Area measurements made using this technique were compared to corresponding manual measurements and used to establish the comparative accuracy of the semi-automated image analysis technique, with a quality assurance study to measure the repeatability of the new technique. For both magnifications and for each tissue component, the quality assurance study showed that the semi-automated image analysis algorithm had better repeatability than its manual equivalent. No significant bias was detected between the measurement techniques for any of the comparisons made using the 26 cases of pancreatic carcinoma. The ratio of manual to semi-automatic repeatability errors varied from 2.0 to 3.6. Point counting would need to be increased to be between 400 and 1400 points to achieve the same repeatability as for the semi-automated technique. The results demonstrate that semi-automated image analysis is suitable for measuring tissue fractions in histological samples prepared with coloured stains and is a practical alternative to manual point counting.     

Evaluation of an automated urinalysis system for testing urine chemistry,microscopy and culture

AIMS: This study was designed to evaluate the performance of an automated urinalysis system that utilised three commercially available instruments, the Clinitek Atlas, Sysmex UF-100 and the Alifax Uro-Quick. METHODS: The results of the automated system for 818 urine samples were compared with the results of manual processing which consisted of phase contrast microscopy, manual dipstick chemistry analysis and culture onto solid media. RESULTS: The correlation between the two methods for urine chemistry was excellent with a concordance of 89, 97, 100 and 98% for pH, blood, glucose and protein, respectively. The quantification of red blood cells and white blood cells had an R2 of 0.855 and 0.92, respectively. A difference scatter plot indicated a trend towards the manual cell count being greater than the UF-100 count as both the red and white blood cell count increased. There was 98% agreement between the automated process and manual culture. CONCLUSIONS: The automated urinalysis system is fully integrated and allows for the cross-checking of urine chemistry and microscopy as well as electronic transfer of data. The automated process was used as a screening procedure and some manual testing was necessary. Automation of urinalysis offers a reduction in variation and has comparable results to manual testing.     

Comparison of manual sleep staging with automated neural network-based analysis in clinical practice

We have compared sleep staging by an automated neural network (ANN) system, BioSleep (Oxford BioSignals) and a human scorer using the Rechtschaffen and Kales scoring system. Sleep study recordings from 114 patients with suspected obstructed sleep apnoea syndrome (OSA) were analysed by ANN and by a blinded human scorer. We also examined human scorer reliability by calculating the agreement between the index scorer and a second independent blinded scorer for 28 of the 114 studies. For each study, we built contingency tables on an epoch-by-epoch (30 s epochs) comparison basis. From these, we derived kappa (kappa) coefficients for different combinations of sleep stages. The overall agreement of automatic and manual scoring for the 114 studies for the classification {wake / light-sleep / deep-sleep / REM} was poor (median kappa = 0.305) and only a little better (kappa = 0.449) for the crude {wake / sleep} distinction. For the subgroup of 28 randomly selected studies, the overall agreement of automatic and manual scoring was again relatively low (kappa = 0.331 for {wake light-sleep / deep-sleep REM} and kappa = 0.505 for {wake / sleep}), whereas inter-scorer reliability was higher (kappa = -0.641 for {wake / light-sleep / deep-sleep / REM} and kappa = 0.737 for {wake / sleep}). We conclude that such an ANN-based analysis system is not sufficiently accurate for sleep study analyses using the R&K classification system.     

Detection of significant bacteriuria by automated urinalysis using flow cytometry

A new flow cytometry-based automated urine analyzer, the UF-50, was evaluated for its ability to screen urine samples for significant bacteriuria. One hundred eighty-six urine specimens from patients attending an outpatient clinic of a university-based hospital were examined. The results obtained with the UF-50 were compared with those obtained by conventional quantitative urine culture. The UF-50 detected significant bacteriuria with a sensitivity of 83.1%, a specificity of 76.4%, a positive predictive value of 62.0%, a negative predictive value of 90.7%, and an accuracy of 78.5%. These results are comparable to those obtained by previously reported screening procedures. Besides detecting significant bacteriuria, the UF-50 can also perform routine urinalysis, including measurement of concentrations of red blood cells, white blood cells, epithelial cells, and casts, within 70 s. This capability renders this new flow cytometry-based urine analyzer superior to previously reported rapid screening methods.     

Urine sediment analysis by the Yellow IRIS automated urinalysis workstation

The Yellow IRIS automated urinalysis workstation (International Remote Imaging Systems, Chatsworth, CA 91311) performs urine sediment analysis with the use of Automated Intelligent Microscopy (AIM). It ranks and counts particles based on size. A split sample study using 268 individual urine specimens was performed comparing sediment analyte detection by the Yellow IRIS with that achieved by a standard manual method. The detection ratio ("positive" specimens detected by the Yellow IRIS divided by "positive" specimens detected by the manual method) for the presence of various analytes, as well as the presence of abnormal numbers of analytes, was determined. The significance of each detection ratio was tested by calculating the McNemar's statistic, which is useful in the evaluation of nonparametric data collected by two different methods on identical specimens. Results were considered abnormal if the red blood count was greater than or equal to three per high-power field, the white blood cell count was greater than or equal to five per high-power field, or squamous epithelial cells were greater than or equal to five per high-power field. The results indicate that the Yellow IRIS enhances the detection of urinary sediment components.     

Normal laboratory values for differential white cell counts established by manual and automated cytochemical methods (Hemalog DTM)

The central 95 percentile estimates of the normal white cell types (as determined by a standard differential count) were calculated from 777 normal individuals. The results were divided into groups by age and sex and expressed both as percentages and as absolute numbers of cells.     

Comparison of manual and automated DNA purification for measuring TREC in dried blood spot (DBS) samples with qPCR

Automated nucleic acid extractions from dried blood spot (DBS) samples promises standardized sample treatment, low error rates, avoidance of contamination and requirement of less hands-on time. In the present study, non-automated and automated column based extraction processes using the QIAamp Investigator procedure were compared for the extraction of DNA from DBS samples. The concentration and the purity of DNA generated were determined by optical density readings. Furthermore qPCR downstream applications using the nucleic acids extracted with the two processes and albumin and T-cell receptor excision circles (TREC) copy numbers were measured and compared. The influence of the time of storage was also investigated by analyzing samples freshly dried and stored up to 11weeks at -20°C from the same individual. Finally, we provide arguments of preferentially choosing the automated procedure for extracting DNAs from DBS samples when downstream qPCR applications are required.     

Strategies for medium-throughput automated genotyping methods

The need to genotype large numbers of individuals has assumed a great scientific and commercial importance in recent years. This has been mirrored by the requirement for and development of technologies for automating sample preparation. In the present article, we describe strategies for the automation of aspects common to many genotyping strategies. These include genomic DNA extraction, upstream polymerase chain reaction (PCR) amplification, post-PCR sample purification and downstream sequencing and/or primer extension of purified PCR products.