Screening for cystic fibrosis by measurement of unstimulated parotid saliva sodium levels

Saliva as a potential tool for cystic fibrosis diagnosis

BACKGROUND

Saliva and sweat are modified by cystic fibrosis (CF). In both cases the chloride and sodium ion concentrations for healthy subjects and CF patients differ, this representing a possible alternative tool for CF diagnosis. In this context, the aim of this study was to compare the concentrations of these ions in saliva samples taken from CF patients and healthy subjects.

METHODS

A case-control study was carried out at a university CF center, in which the saliva samples were analyzed on an ABL 835 Radiometer® to determine the ion concentration.

RESULTS

For the CF patients (n = 80) the values for the biochemical parameters of chloride, potassium and sodium ion concentration were higher (p < 0.009) and the volume and pH of the saliva were lower than in the case of healthy subjects (p < 0.009). For the healthy subjects group (n = 84) versus CF patients, according to the ROC curve, the values for sodium were: cutoff: 13.5 mmol/L, sensitivity: 73.4%, specificity: 70.6%; and for chloride: cutoff: 20 mmol/L, sensitivity: 68.1%, specificity: 72.9%.

CONCLUSIONS

The chloride and sodium concentrations in the saliva samples were higher for CF patients in comparison with healthy subjects. Thus, saliva as a tool for CF diagnosis can be considered a new challenge, and a population study including patients in all age classes needs to be performed, in different countries over the world, to extend the database to include a broad spectrum of information in order to identify normal ion concentration ranges for CF patients according to age, genotype and environment.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2614233148750145.

Sodium, calcium, and magnesium levels in nails of children with cystic fibrosis of the pancreas

Nail sodium, calcium, and magnesium levels were measured in 15 children with cystic fibrosis (CF) of the pancreas and compared with values found in 78 controls. There was a significant increase in the mean value of all three parameters in the CF group. There was an overlap in the values between the affected and control groups for all three measurements. Summing the sodium and calcium values or the sodium, calcium, and magnesium values gave a clear-cut separation between the groups, this being better in the latter case. It is felt that this approach might also prove fruitful in the detection of the heterozygote.