Congenital Adrenal Hyperplasia (CAH) includes a group of disorders in which the cortisol production by adrenals is lowered. Cortisol is a steroid hormone necessary to maintenance of blood sugar level, partial maintenance of body fluids and electrolytes and protection of the body against stress. CAH cannot be cured, but it can be effectively treated by steroid substitution therapy if detected in early stage of life and disease course. Because of large individual variation in cortisol secretion, it is also important to monitor treatment very carefully. The means to determine an appropriate replacement dose includes measurement of serum/plasma17-hydroxyprogesterone. Labsystems Diagnostics' Neoscreen 17-OH-Progesterone FEIA test allows quantification of 17-hydroxyprogesterone in dried blood spot samples.
Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is the most common human enzyme deficiency; an estimated 400 million people worldwide are affected by this enzymopathy (6). With regards to the demographics of G6PD deficiency, most of the affected individuals reside in Africa, the Middle East, and Southeast Asia. The G6PD enzyme catalyzes an oxidation/reduction reaction. The G6PD enzyme functions in catalyzing the oxidation of glucose - 6 - phosphateto 6 - phosphogluconolactone while concomitantly reducing nicotinamide adenine dinucleotide phosphate (NADP+ ) to NADPH. This is the first step in the pentose phosphate pathway and is essential for the synthesis of both DNA and RNA (7). G6PD is also responsible for maintaining adequate levels of NADPH inside he cell.
Galactosemia is an inherited metabolic abnormality comprising three distinctive clinical entities of the galactose pathway defects. Classic galactosemia is due to -Dgalactose- 1-phosphate-uridyl-transferase (GALT) defect (1). The test principle is based on extraction of Galactose & Galactose-1-phosphate from dried blood spot followed by enzymatic conversion of Galactose-1-phosphate & Galactose. Two kinds of extraction methods (acidic and heat) can be used for extraction step. After extraction Galactose-1-phosphate converts to Galactose in a reaction catalyst by alkaline phophatase enzyme Then this Galactose & extracted Galactose from dried blood spot converts to Galactonolactone by Galactose Dehydrogenasis & NAD coenzyme. The resulted NADH reduces Tetrazolium salt indicator dye from yellow to pink or red color. The figure demonstrates the reaction cycles. Final color change is used for colorimetric measurement (490 nm ) spectrophotometrically.
Cystic Fibrosis (CF) is an autosomal recessive disorder affecting the lungs, pancreas, intestine and liver. CF is the most common in Caucasians with an incidence rate 1:2500 newborns. CF is caused by mutation in the gene for the protein cystic fibrosis transmembrane conductance regulator (CTFR) [1,2]. Large-scale neonatal screening for CF is performed by indentification of increased levels of immunoreactive trypsinogen (IRT) in blood. Diagnosis of CF is suggested by manifestations of chronic sinopulmonary disease and exocrine pancreatic insufficiency, confirmed by a sweat test. Neoscreen IRT EIA is a solid phase Enzyme immunoassay in which IRT is eluted from dried blood disks. It simultaneously forms a sandwich between the solid phase, coated with an antibody that recognizes Trypsinogen-1 (IRT-1) and excess of conjugate and unbound hIRT is washed away after incubation and the enzymatic reaction with Chromogenic substrate solution ( 3,3',5,5'-Tetramethylbenzidine (TMB) is performed.
Congenital hypothyroidism (CH) is an endocrine disorder of newborns characterized by the decreased levels of thyroid hormones: thyroxine (T4) and triiodothyronine (T3) in periferal blood. In early perinatal period manifestations of CH are often non-specific, subtle or even non-existent [1-2]. However, the disease, if undiagnosed and untreated, leads to severe mental retardation, as well as to growth and developmental disturbances.