Product Spotlight: Acusera Immunoassay Speciality 2 Control
The Randox Acusera Immunoassay Speciality II quality control is designed to complement our Immunoassay Premium and Premium Plus controls. Assayed, instrument specific target values and ranges are provided for 4 complex immunoassay parameters.
Features & Benefits
- Lyophilised for enhanced stability
- 100% human serum
- Assayed target values provided for 4 parameters
- Stable to expiry date at 2°C – 8°C
- Reconstituted stability of up to 5 days at 2°C – 8°C and 4 weeks at -20°C
Procalcitonin (PCT), a protein that consists of 116 amino acids, is the peptide precursor of calcitonin, a hormone that is synthesized by the parafollicular C cells of the thyroid and involved in calcium homeostasis.
Procalcitonin is also produced by the neuroendocrine cells of the lung and intestine and is released as an acute-phase reactant in response to inflammatory stimuli, especially those of bacterial origin. This raised procalcitonin level during inflammation is associated with bacterial endotoxin and inflammatory cytokines.
Procalcitonin (PCT) versus C-reactive protein (CRP)
CRP is the most common laboratory marker used in the clinical setting to evaluate systemic inflammatory response to an infectious agent.
Procalcitonin is a more useful diagnostic inflammation parameter than CRP in patients with pediatric neutropenic fever, both in estimating the severity of infection and the duration and origin of the fever. Procalcitonin is also a more reliable parameter in the diagnosis of bacterial sepsis, allowing better differentiation among sepsis-related fatalities.
A calcitonin assay is helpful in identifying patients with nodular thyroid disease. It is often performed in the hope of identifying early MTC. Successful treatment of MTC depends on early detection; late detection confers a poor prognosis. In addition, calcitonin levels are reported to be increased in other malignancies, such as carcinoid tumors, lung carcinoma, melanoma, pancreatic and breast carcinoma, and pheochromocytoma.
Calcitonin is produced and released by parafollicular cells of the thyroid. Calcitonin is derived from larger precursors. Precalcitonin is cleaved to procalcitonin, which is further cleaved to immature calcitonin and then to mature calcitonin, a monomer of a 3.5-kd peptide composed of 32 amino acids, which is the only biologically active form.
Calcitonin’s precise physiologic role in humans remains to fully understood. It is known to act on the bones, kidneys, and gastrointestinal tract, binding directly to osteoclasts, thereby directly inhibiting osteoclastic bone resorption. Although this inhibition may be important in short-term control of calcium loads, it is short-lived and likely plays an insignificant role in overall calcium homeostasis. Calcitonin also inhibits the action of parathyroid hormone and vitamin D. 
Gastrin testing is employed in the diagnosis of gastrinoma, either with or without Zollinger-Ellison syndrome, and in the investigation of pernicious anemia and achlorhydria.
In patients who have undergone antrectomy with vagotomy, gastrin levels are reduced. In contrast, gastrin levels are increased in Zollinger-Ellison syndrome.
Renin, also known as Angiotensinogenase, is an enzyme involved in the renin–angiotensin aldosterone system (RAAS), which regulates the body’s water balance and blood pressure level. The system regulates the extracellular volume in the blood plasma, lymph and interstitial fluid, as well as controlling constriction of the arteries and blood vessels. It is secreted by the kidney from specialized cells called granular cells and has a fundamental role in hypertension development. Over activation of this system contributes to hypertension and associated end-organ damage.
The secretion of renin is stimulated by the following three factors:
- When a fall in arterial blood pressure is detected by pressure sensitive receptors (baroreceptors) in the arterial vessels.
- When a decrease in sodium chloride (salt) is detected in the kidney by the macula densa in the juxtaglomerular apparatus.
- When sympathetic nervous system activity is detected through beta1 adrenergic receptors.
Immunoassay Spec II EQA
A. Sofronescu and E. Staros, “Calcitonin”, Emedicine.medscape.com, 2015. [Online]. Available: https://emedicine.medscape.com/article/2087580-overview#a4. [Accessed: 16- Jul- 2018].
J. Lin, S. Yap and E. Staros, “Procalcitonin”, Emedicine.medscape.com, 2015. [Online]. Available: https://emedicine.medscape.com/article/2096589-overview#a4. [Accessed: 16- Jul- 2018].
B. Devkota and E. Staros, “Gastrin”, Emedicine.medscape.com, 2014. [Online]. Available: https://emedicine.medscape.com/article/2089092-overview#a4. [Accessed: 16- Jul- 2018].
T. Meštrović, “Renin Clinical Applications”, News-Medical.net, 2015. [Online]. Available: https://www.news-medical.net/health/Renin-Clinical-Applications.aspx. [Accessed: 16- Jul- 2018].
D. Mandal, “Renin (Angiotensinogenase)”, News-Medical.net, 2014. [Online]. Available: https://www.news-medical.net/health/Renin-Angiotensinogenase.aspx. [Accessed: 16- Jul- 2018].
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