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Haematological Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
When an automated analyser processes an FBC sample, it measures: Haemoglobin concentration (Hb conc, g/L)MCV, femtolitres (fL)WBCNeutrophil countLymphocyte countPlatelet count
Semen Analysis and Sperm Washing Techniques
Published in Claude Gagnon, Controls of Sperm Motility, 2020
The Makler chamber is a high-precision unit with a depth of 10 μm and a ruled area of 1 mm2 divided into 100 squares so that the number of spermatozoa seen in ten squares corresponds the concentration in millions per milliliter (e.g., 175 spermatozoa seen across the whole grid = 17.5 × 106/ml). The Horwell Chamber has the same basic design, but seems to be manufactured to lower precision and uses a standard haemocytometer cover glass. Great care must be taken not to over fill these chambers; the maximum sample volume that should be used is 5 μl. In routine use, these chambers are prone to substantial errors10 and cannot be recommended for laboratories wishing to perform semen analyses to presently accepted standards.10-12 However, their use in conjunction with the new automated analyzers may be essential.
Analytical Toxicology of Vitreous Humor
Published in Steven H. Y. Wong, Iraving Sunshine, Handbook of Analytical Therapeutic Drug Monitoring and Toxicology, 2017
Not surprisingly, earlier investigators used procedures for vitreous humor specimens that they used for other specimens for the same analytes, procedures that are not used very often at the present time. Felby and Olsen9 used alcohol dehydrogenase and the Widmark method for ethanol. In a separate study, Felby and Olsen10 used ultraviolet spectroscopy to determine barbiturates and meprobamate in vitreous humor, blood, and liver. Coe and Sherman11 analyzed for ethanol with a diffusion/dichromate procedure. Sturner and Garriott12 described using ultraviolet spectrophotometry and GLC for detection and quantitation of numerous different drugs in both vitreous humor and blood. They also used RIA for determination of digoxin and insulin. Blumenfeld et al.13 used a variety of methods to measure various analytes in sudden infant death syndrome cases: enzymatic (urease) method for urea nitrogen; atomic absorption for calcium and magnesium; coulometric-amperometric method for chloride; flame photometry for potassium and sodium; a Jaffe method for creatinine; and a trichloroacetic acid-Ponceau S dye method for total protein. Several reports describe using automated analyzers for determination of various electrolytes and similar analytes. The automated analyzers at that time incorporated colorimetric procedures for chloride and glucose and flame photometers for sodium and potassium. In addition to using a Technicon AutoAnalyzer for sodium, chloride, potassium, urea nitrogen, glucose, creatinine, SGOT and SGPT, Leahy and Farber14 also used electrophoresis on a cellulose acetate medium for separation of lactate dehydrogenase isoenzymes. One of the problems with analyzing vitreous humor specimens in automated analyzer systems occurs because of the viscosity of the specimens. At the Southwestern Institute of Forensic Sciences/Dallas County Medical Examiner’s Office,15 vitreous humor specimens were submitted to the adjacent hospital clinical chemistry laboratory for electrolyte analyses. The clinical laboratory had significant difficulty with plugged flow lines associated with analyzing our specimens. After our laboratory purchased an automated analyzer system, we had similar problems caused by formation of fibrous precipitates in some of the lines. Ultimately, we discovered that the acid solution needed for the CO2 analysis was the responsible reagent; because we did not use the CO2 results, we replaced the acid solution with water, and the problem was resolved. (This automated analyzer system used ion-selective electrodes for the detection of the various analytes.) As described previously, Coe2 recommends that vitreous humor specimens be centrifuged and that the supernatant portion be used to prevent clogging of the small diameter tubes often used in modern analytical instruments.
The role of paraoxonase and myeloperoxidase as oxidative stress markers in pregnant women with hypothyroidism
Published in Gynecological Endocrinology, 2022
Suat Cakina, Eren Pek, Onur Ozkavak, Deniz Kocyigit, Fatma Beyazıt
The Relassay Myeloperoxidase Chlorination Activity Assay Kit and The Relassay Myeloperoxidase Peroxidation Activity Assay Kit are quantitative and colorimetric assay kits for measuring the myeloperoxidase activity within a sample. In The Relassay Myeloperoxidase, Taurine chloramine is formed through the reaction of taurine with hypochlorous acid catalyzed by MPO. DTNB is a colorless product developed by the chromophore TNB and taurine chloramine reaction. The amount of enzyme that hydrolyzes the substrate and produces taurine chloramine is considered one unit of MPO activity and consumes 1.0 μmol of TNB per minute. In The Relassay Myeloperoxidase Peroxidation Activity Assay Kit, MPO catalyzes odianisidine to colored o-dianisidyl radical using H2O2. Kinetic activity is measured by examining the increased absorbance at 412 nm wavelength. This kit is easily adapted to automated analyzers and can be used manually.
Revisiting approaches to and considerations for urinalysis and urine culture reflexive testing
Published in Critical Reviews in Clinical Laboratory Sciences, 2022
Allison B. Chambliss, Tam T. Van
While the basic principles of UA laboratory methodologies have remained largely consistent, varying degrees of automation have allowed faster and more objective results. The color changes on chemical UA dipsticks, historically inspected visually, are now commonly read on automated analyzers using reflectance photometry. Because automated analyzers typically use the same dipstick strips as manual methods, results tend to correlate well [3]. Automated analyzers remove operator subjectivity, thus standardizing color interpretation and eliminating variance from reaction timing. Automated analyzers are also typically higher throughput than manual reading, and some analyzers offer sample transfer automation to a urine microscopy analyzer. Increasingly, point-of-care UA applications utilize electronic dipstick readers, which may offer electronic interfacing of results to the electronic health record [4]. Notably, some substances in urine interfere with the chemical reactions, causing false negative or false positive results [2]. The manufacturer may provide recommendations for follow-up testing when specimens generate an instrument flag.
A positive association between interleukin-1 receptor antagonist and insulin resistance in postmenopausal women
Published in Gynecological Endocrinology, 2018
Chii-Min Hwu, Hung-Hsiang Liou, Chung-Jen Lee, Bang-Gee Hsu
The participants visited our research clinic at 8 a.m. after an overnight fast. Anthropometric and blood pressure (BP) measurements were taken using standard protocols reported before [12]. Fasting blood samples were collected thereafter. We interviewed the subjects for their personal, medical, and drug history. Plasma glucose was measured using the glucose oxidase technique on a glucose analyzer. Measurements of serum biochemistry were done in an automated analyzer. Insulin was assayed by using a chemiluminescence immunoassay, which had an intra-assay coefficient of variation (CV) of 3.7% and inter-assay CV of 4.4%. Plasma levels of IL-1Ra were determined by solid phase enzyme-linked immunosorbent assay (Quantikine, R&D Systems, Minneapolis, MN). The lowest level of detection was 18.3 pg/mL. Mean intra-assay and inter-assay CVs were 4.6 and 7.6%, respectively.