Cystic fibrosis sweat analysis

Chloride 10 -1 -57, CN , 1, Br, S2( , SCN- Water analysis, soil extracts Chloride in sweat (cystic fibrosis) Food Analysis... 

In addition to blood, certain types of specimens are submitted to the Pediatric laboratory which would not be commonly seen elsewhere. An example of this is sweat for analysis of chloride. The process of obtaining the sweat by iontophoresis usually falls to the personnel of the Laboratory of Neonatology (17). Stool for analysis of lipids and trypsin is more commonly submitted to the Laboratory of Neonatology than to the laboratory which services the adult population. The reason for this is that one is screening for certain intestinal diseases characteristic of infants and newborns which are rare in adults. Such conditions would be celiac disease, cystic fibrosis and others. 

For the detection of cystic fibrosis, which is a quantitative analysis, the situation is different because such an analysis is performed only in the hospital environment. This requires that the conditions to execute such a test with the sensor system can be chosen and controlled in such a way that possible interference is avoided. In addition, for cystic fibrosis detection, the analyst is interested in the electrolyte concentration of the sweat, regardless of how this sweat formation was obtained (high temperature, exercise), with the implication that the sources of interference are much less for cystic fibrosis detection than was the case for the detection of low sugar level in the blood. The complication in this type of analysis is that it is not enough to... 

The analysis of sweat for increased electrolyte concentration is used to confirm the diagnosis of cystic fibrosis (CF). CF is recognized as a syndrome with a wide spectrum of clinical presentations associated with a defect in the cystic fibrosis transmembrane conductance regulator protein (CFTR), a protein that normally regulates electrolyte transport across epithelial membranes. (For a more detailed discussion of CF, see Chapter 40.) Several hundred mutations of CFTR have been identified. Although mutational analysis is available, it is not informative in all cases, and the sweat test remains the standard for diagnostic testing. ... 

Chloride analyses in the clinical setting are primarily concerned with levels in the sweat for diagnosing cystic fibrosis, although in vitro blood analysis is easily accomplished. 

Within the biomedical field, the application of chloride ion-selective electrodes has largely been devoted to sweat analysis in relation to cystic fibrosis screening and diagnosis [159,251—271]. The disease, in which there is a malfunction of exocrine glands, can be readily diagnosed from the elevated chloride ion levels in patients sweat ( 100 mmol dm" ) compared with a normal ( 25 mmol dm ). Reasonably accurate monitoring of newborns, infants and children may... 

Solid-state sensors for chloride, iodide, and fluoride are based on the solubility product of silver chloride or silver iodide particles in silicone rubber and a doped lanthanum fluoride single crystal, respectively. The fluoride-selective electrode was applied for the analysis of urine and bone tissue of people exposed to industrial sources as well as for control of therapeutic fluoride application for osteoporosis, whereas the chloride-selective sensor was applied to the analysis of sweat for the diagnosis of cystic fibrosis. In solid-state contact electrodes the solvent polymeric membrane is directly contacted to the solid field transducing element, although the reference electrode is separated from the ion-selective sensing pad. 

---