Product Intelligence by Katriona Scoffin
linical chemistry analyzers run assays on clinical samples such as blood serum, plasma, urine, and cerebrospinal fluid to detect the presence of analytes relating to disease or drugs. Clinical chemistry analyzers are used in a variety of settings, including small clinics, research labs, and high-throughput hospital labs. They are also used at the point-of- care, such as in physicians’ offices and patient bedsides.
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Analytes commonly include enzymes, substrates, electrolytes, specific proteins, drugs of abuse, and therapeutic drugs. The results give clinicians feedback on toxicology and on renal, cardiac, and liver function.
How does a clinical chemistry
analyzer work? Analyzers are highly automated to maximize throughput, to improve user safety from biohazards, and to diminish the risk of cross-contamination. Samples are loaded into the machine and tests are programmed by the user. A probe measures an aliquot of sample and places it into a reaction vessel. Reagents are added from an on-board refrigerated supply. Incubation time is allowed, if required; then photometric or ion-selective electrode (ISE) testing determines the concentration of analyte. Results are displayed on screen or sent to a printer or computer.
Choosing a chemical analyzer Your choice of chemical analyzer will depend on the types of test you
wish to run and the throughput you require. Other factors include sam- ple handling, degree of automation, data management, operating costs, footprint, and whether the machine can handle micro volume samples.
Tests and analytical methods The most common test method is photometry. The sample is mixed with
the appropriate reagent to produce a reaction that results in a color. The concentration of the analyte determines the strength of color produced. The photometer shines light of the appropriate wavelength at the sample and measures the amount of light absorbed, which is directly correlated to the concentration of the analyte in the sample.
The other major analytical method is the use of ion selective electrodes to measure ions such as Na+
, K+ , Cl– , and Li+ . An ISE is a sensor that deter-
mines the concentration of ions in a solution by measuring the current flow through an ion selective membrane.
The RX daytona from Randox (Kearneysville, WV;
www.randox.com) is a compact benchtop analyzer (see Figure 1). It runs colorimetric and UV photometric methods at eight different wavelengths from 340 to 700 nm, with endpoint, kinetic, monochromatic, bichromatic, turbidimetric,
Figure 1 – The RX daytona from Randox is a compact, fully automated benchtop clinical chemistry analyzer suitable for use in small- to medium- throughput laboratories. (Image used with permission of Randox.)
sample, and reagent blanking options. The light source is a halogen tungsten lamp. An optional ISE unit can be added. The test menu in- cludes over 100 tests for applications in the following categories:
Clinical Autoimmune
Basic metabolic profile Bone profile Cardiac
Comprehensive metabolic profile Diabetes
Electrolytes
Hemolytic anemia Hepatic function
Inflammation and infection Lipids
Neonatal screening Nutritional status Pancreatic function Renal function
Manufacturers continually add to their test menus. For example, Bio-Rad (Hercules, CA;
www.bio-rad.com) recently introduced new Bio-Plex® Pro™
AMERICAN LABORATORY • 20 • JUNE/JULY 2013 Toxicology
Therapeutic drugs Drugs of abuse
Proteins Specific proteins Research
Biotechnology Antioxidants
Food and wine testing
powered by Clinical Chemistry Analyzers Technology
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