Table 5.

Validity of field technique using syringe extraction of sweat and compact Horiba analysis: SYRINGE HORIBA versus CENTRIFUGE HPLC for sweat [Na⁺] and [K⁺].

	Sweat [Na+]	Sweat [K+]
Mean difference ± SD (mEq/L)	3.97 ± 10.87*	0.50 ± 0.48*
95% CI of mean difference (mEq/L)	2.49–5.45	0.42–0.59
ICC	0.93*	0.84*
SEE (mEq/L)	8.68	0.44
TEM (mEq/L)	7.68	0.34
CV (%)	12.54	8.48

n = 210 for sweat [Na⁺] and 116 for sweat [K⁺]. CV. coefficient of variation; CI, confidence interval; HPLC, ion chromatography using the Dionex ICS‐3000; HORIBA, Horiba B‐722 for sweat [Na⁺] and Horiba B‐731 for sweat [K⁺]; ICC, intraclass correlation coefficient (based on two‐way mixed ANOVA, absolute agreement, average measures); SD, standard deviation; SEE, standard error of the estimate; TEM, typical error of measurement; *P < 0.001.