A Novel Automated Slide-Based Technology for Visualization, Counting, and Characterization of the Formed Elements of Blood: A Proof of Concept Study.

CONTEXT: - A novel automated slide-based approach to the complete blood count and white blood cell differential count is introduced. OBJECTIVE: - To present proof of concept for an image-based approach to complete blood count, based on a new slide preparation technique. A preliminary data comparison with the current flow-based technology is shown. DESIGN: - A prototype instrument uses a proprietary method and technology to deposit a precise volume of undiluted peripheral whole blood in a monolayer onto a glass microscope slide so that every cell can be distinguished, counted, and imaged. The slide is stained, and then multispectral image analysis is used to measure the complete blood count parameters. Images from a 600-cell white blood cell differential count, as well as 5000 red blood cells and a variable number of platelets, that are present in 600 high-power fields are made available for a technologist to view on a computer screen. An initial comparison of the basic complete blood count parameters was performed, comparing 1857 specimens on both the new instrument and a flow-based hematology analyzer. RESULTS: - Excellent correlations were obtained between the prototype instrument and a flow-based system. The primary parameters of white blood cell, red blood cell, and platelet counts resulted in correlation coefficients (r) of 0.99, 0.99, and 0.98, respectively. Other indices included hemoglobin (r = 0.99), hematocrit (r = 0.99), mean cellular volume (r = 0.90), mean corpuscular hemoglobin (r = 0.97), and mean platelet volume (r = 0.87). For the automated white blood cell differential counts, r values were calculated for neutrophils (r = 0.98), lymphocytes (r = 0.97), monocytes (r = 0.76), eosinophils (r = 0.96), and basophils (r = 0.63). CONCLUSIONS: - Quantitative results for components of the complete blood count and automated white blood cell differential count can be developed by image analysis of a monolayer preparation of a known volume of peripheral blood.

Accuracy evaluation of a new glucometer with automated hematocrit measurement and correction.

BACKGROUND: Blood glucose meters are widely used in point of care testing, however, many studies have shown inaccuracies in the glucose measurement due to a number of factors. The present study evaluated the accuracy of a new glucometer capable of simultaneous measurement of patient's hematocrit with algorithmic adjustment of glucose result. This meter was compared with a reference method and 2 other existing meters widely used in the market. METHODS: Venous whole blood samples from healthy volunteers were pooled and reconstituted to produce 5 different hematocrit (30-60%) concentrations. Each hematocrit specimen was spiked to produce 4 different glucose (50-500 mg/dl) concentrations. RESULTS: Hematocrit measured by the new meter correlated well with the reference method. Mean percentage error differences, compared to the reference method, showed obvious differences between existing meters across the wide hematocrit range at various glucose concentrations. The new meter showed a steady and consistent glucose concentrations compared to the reference method. CONCLUSION: The new glucometer, which simultaneously measures hematocrit and performs automated correction for the hematocrit effect, provides a glucose result with improved accuracy. Its measurement of hematocrit from the same blood sample will eliminate the need for additional collection of blood or measurement using another method.

Noninvasive testing in the clinical laboratory.

We have chosen to provide a brief review of only three of the numerous existing, emerging or future applications of novel technologies that provide noninvasive testing. Clinical laboratory testing over the recent decades has been characterized by a remarkable increase in the variety and volume of [figure: see text] information made available to assist physicians in the practice of medicine. Among current trends that facilitate prompt delivery of results, noninvasive testing holds great promise. Technologies that already exist or that have not yet been developed may extend the opportunities to exploit this approach. Noninvasive testing has other obvious attractive features; safety, painlessness and adaptability to special care situations. Our profession may well enjoy additional vitalization from the further evolution of this facinating and important field.

Confirmation of the Department of Transportation criteria for a substituted urine specimen.

The purpose of this study was to determine whether people could naturally produce urine sufficiently dilute to meet the federal criteria for a "substituted" specimen. The United States Department of Transportation Regulations (49 Code of Federal Regulations Part 40) defines a urine specimen as substituted if it has a creatinine concentration of < or = 5 mg/dL and a specific gravity of < or = 1.001 or > or = 1.020. These criteria have been criticized based on the contention that an insufficient number of specimens had been tested from the same urine sample for both creatinine and specific gravity measurements. We reviewed the results of 803,130 random urine specimens measured for creatinine and/or specific gravity in a hospital-based laboratory. In this database, 13,467 urine specimens had both creatinine and specific gravity measurements. None of these 13,467 paired urine specimens met the lower limit of specific gravity (< or = 1.001) and creatinine (< or = 5 mg/dL) criteria for a Department of Transportation substituted specimen. We also examined the medical records of those patients meeting even one of the two criteria; creatinine concentration < or = 5 mg/dL or specific gravity < or = 1.001. These patients were neonatal, moribund, or so severely ill that essentially none could have been among the working population. These data in patients with various pathologic states support our belief that normal individuals do not produce urine dilute enough to meet the lower limit of the specific gravity (< or = 1.001) and creatinine (< or = 5 mg/dL) required for meeting substituted specimen criteria. Eleven patients met the criteria for a substituted specimen, with elevated specific gravity of > or = 1.020 and creatinine concentration of < or = 5 mg/dL; however, these patients were seriously ill or terminally ill.