Desk-top systems for office chemistries
Article Abstract:
Four desk-top systems that can analyze blood chemistry are now commonly used in physicians' offices. Two have previously been reviewed, and this article discusses the Seralyzer, equivalent in cost to the others, and the Vision, which is fully automated and much more costly. The Seralyzer, from Miles Diagnostics, uses plastic strips impregnated with dry reagents. The operator has to dilute and then accurately pipet (dispense) a 30-microliter (ul) volume of a plasma (blood minus blood cells) or serum (blood fluid left after clotting) sample onto the reagent strip. The strip is then analyzed by the machine; results are displayed, but a user-supplied printer is needed to obtain a printout. Two doses of calibrators for each test are supplied, only one test can be run at a time, and the maximum rate is 26 tests per hour. Seventeen different tests are available. Some skill is required for correct use of the Seralyzer, and of the four systems, results with the Seralyzer varied the most. However, satisfactory comparisons with standard laboratories have been reported for 14 tests, but cholesterol measurements may vary by over 5 percent, which exceeds recommended reliability goals. The Vision System, from Abbott, uses test packs, which are sealed units containing several chambers. Microliter volumes of blood obtained by finger sticking or standard blood collection are placed in capillary (very thin) tubes placed in test packs; accurate volume measurement is unnecessary. The test pack is placed in the centrifuge portion of the system, which separates cells from plasma, and a mechanism changes the pack so that plasma moves into another chamber for mixing with reagents. Test packs for 25 tests are available. Results from the Vision System were equivalent to those from standard laboratories, and varied less than the three other desk-top systems. Control values should be run daily, and recalibration, which may last over four weeks, should be performed when new reagent batches are used or controls show a drift in accuracy. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Medical Letter on Drugs and Therapeutics
Subject: Health
ISSN: 0025-732X
Year: 1990
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The Reflotron for office chemistries
Article Abstract:
The Reflotron is a desktop device that can do clinical chemistry tests on very small volumes of blood, with each test taking two to three minutes. Clinical chemistry tests are done using multilayered strips containing dry chemicals, and a separate strip is used for each analysis. Various enzymes and substances in the blood can be analyzed, including glucose, cholesterol, triglycerides, and hemoglobin. A blood sample is taken from an individual by finger stick, and placed on the top of the strip, which separates out the different components of the blood. The strip with the blood sample is then placed into the Reflotron to be analyzed. Some studies show that measurements obtained using the Reflotron correspond to values of enzymes and substances obtained by standard methods. Persons operating the Reflotron should be adequately trained and controls must be run routinely. The Ektachem is another desktop system that uses dry-chemistry methods. In comparison with the Reflotron, the Ektachem can analyze a larger number and wider variety of samples, but is more expensive. The Reflotron is a reasonably accurate clinical chemistry system, capable of running a limited variety of tests on small volumes of whole blood. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Medical Letter on Drugs and Therapeutics
Subject: Health
ISSN: 0025-732X
Year: 1989
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Patient-controlled analgesia
Article Abstract:
Patient-controlled analgesia (PCA) is a method whereby patients control their pain by using a device that delivers analgesics, agents that relieve pain, directly into the circulation. PCA has been used to relieve pain after an operation or during labor, sickle cell crisis, and cancer. Most PCA devices consist of a syringe, or chamber, containing the analgesic and an electromechanical unit that controls medication delivery when the patient presses a button. The injection of opioid analgesic agents into muscle results in unpredictable amounts of the medication in the blood. PCA dispenses constant and uniform analgesia or pain relief, and provides patients reassurance and a sense of control, sometimes leading to decreased use of medication. The procedure and dosages used with PCA devices are described. PCA with narcotic agents does not appear to cause addiction, although minor adverse effects, such as nausea, vomiting, constipation, sweating, excessive itching, and respiratory depression have been reported. The problems that have been reported, mainly due to operator error, include fatal overdosage. PCA appears to have several advantages over intramuscular injection of opioid analgesics. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Medical Letter on Drugs and Therapeutics
Subject: Health
ISSN: 0025-732X
Year: 1989
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