Low textbook sweat samples are considered unreliable for the diagnosis of cystic fibrosis, based on the assertion that sweat conductivity and chloride are reduced at lower sweating rates. We aimed to re-evaluate the conjunction between sweat notebook and check results.

We reviewed all sweat tests performed in our college to assess the correlation between sweat album and conductivity, and between sweat book and sweat chloride. We as well compared results between pairs of sweat tests taken simultaneously from a unmarried patient, one with sweat publication below and the other above the currently universal minimum jotter (15 µl).

A enervated inverse analogy between sweat manual and sweat conductivity was commence (n=1500, R²=0.105, p«0.001). There was no correlation between sweat volume and sweat chloride (n=463, R²=0.002, p»0.05). In discordant pairs (one below and one exceeding the regular minimum volume), the niggard examination backwash in the low volume morals was slightly higher than its counterpart. In 76 such pairs, scrimpy conductivity was 41.1±14.6 mmol/l in the lower volume sample, compared with 36.8±16.0 mmol/l in the higher volume criterion (p«0.001). Similarly, in 33 of the pairs, parsimonious sweat chloride was 28.4±15.7 mmol/l in the lower volume instance compared with 25.1±15.2 mmol/l in the higher volume specimen (p=0.004).

A standard sweat conductivity and/or chloride cost from a sweat volume «15 µl in a patient whose clinical symptoms are not perfect suggestive of cystic fibrosis, renders this diagnosis unlikely. In contrast, elevated sweat chloride or conductivity measured from a exemplification whose volume is «15 µl may equate an artefact related to the low volume.