Abstract
IntroductionThe investigation of platelet function by aggregometry requires specialist equipment and is labour intensive. We have developed an automated platelet aggregation method on a routine coagulation analyser.MethodsWe used a CS-2000i (Sysmex) with prototype software to perform aggregation in platelet-rich plasma (PRP), using the following agonists: ADP (0.5–10 μm), epinephrine (0.5–10 μm), collagen (0.5–10 mg/μL), ristocetin (0.75–1.25 mg/mL) and arachidonic acid (0.12–1.0 mm). Platelet agonists were from Hyphen Biomed, and an AggRAM aggregometer (Helena Biosciences) was used as the reference instrument.ResultsCS-2000i reaction cuvette stirrer speed was found to influence reaction sensitivity and was optimized to 800 rpm. There were no clinically significant changes in aggregation response when the PRP platelet count was 150–480 x 109/L, but below this there were changes in the maximum amplitude (MA) and slope (rate). Dose response with each of the agonists was comparable between CS-2000i and an AggRAM aggregometer and normal subjects receiving antiplatelet drugs. Aggregation imprecision was similar on both the CS-2000i and AggRAM systems, with a cv for 2–5 μm ADP MA and slope varying between 3–12%.ConclusionOur preliminary studies indicated that optimal sensitivity using the CS-2000i was obtained with a reaction cuvette stirrer speed of 800 rpm and a PRP platelet count of 200–300 x 109/L; aggregation with a PRP count <100 x 109/L showed poor sensitivity. Imprecision and detection of antiplatelet drug effects was similar between the CS-2000i and AggRAM. These data demonstrate that CS-2000i is comparable to a stand-alone aggregometer, although CS-2000i has the advantages of walk-away technology and also required a smaller sample volume than the AggRAM (44% less).
Highlights
Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder of adrenal steroid biosynthesis most commonly caused by mutations or deletions in the CYP21A2 gene
Current treatment regimens do not match the circadian rhythm often leading to poor control of the disease despite the use of supraphysiological doses
57 (53Á3%) patients were in the age group 0–9Á9 years, 37 (34Á6%) in the age group 10–14Á9 years and 13 (12Á1%) were in the age group ≥15 years
Summary
Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder of adrenal steroid biosynthesis most commonly caused by mutations or deletions in the CYP21A2 gene. This leads to a variable deficiency of the enzyme 21-hydroxylase (P450c21) leading to a range of manifestations [salt-wasting type (SW CAH), simple virilizing type (SV CAH), nonclassic type (NC CAH)]. Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder of adrenal steroid biosynthesis most commonly caused by mutations or deletions in the CYP21A2 gene.. Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder of adrenal steroid biosynthesis most commonly caused by mutations or deletions in the CYP21A2 gene.1 This leads to a variable deficiency of the enzyme 21-hydroxylase (P450c21) leading to a range of manifestations [salt-wasting type (SW CAH), simple virilizing type (SV CAH), nonclassic type (NC CAH)]. Reduced cortisol stimulates adrenocorticotrophic hormone secretion via negative feedback which leads to adrenal hyperplasia and increased adrenal androgen production.. Reduced cortisol stimulates adrenocorticotrophic hormone secretion via negative feedback which leads to adrenal hyperplasia and increased adrenal androgen production.2 These individuals have decreased adrenal medullary function which has been suggested to lead to obesity and insulin resistance (IR) via the leptin pathway.. Current treatment regimens do not match the circadian rhythm often leading to poor control of the disease despite the use of supraphysiological doses.
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