V. Neumeister et al., SIMULTANEOUS DETERMINATION OF FECAL FAT, NITROGEN, AND WATER BY NEAR-INFRARED REFLECTANCE SPECTROSCOPY, Journal of pediatric gastroenterology and nutrition, 25(4), 1997, pp. 388-393
Background: Determinations of fecal fat and nitrogen reveal evidence o
f malabsorption and assist in estimating the efficacy of pancreatic en
zyme treatment. Seventy-two-hour stool collection. with chemical analy
sis of fecal fat, and Kjeldahl's method for measurement of fecal nitro
gen are generally accepted as standard methods for making these determ
inations. However, these traditional methods are expensive, time-consu
ming, and cumbersome. This study evaluated the efficiency and validity
of an alternative method, using near-infrared reflectance spectroscop
y (NIRS) and compared results with those of the standard methods. Meth
ods: Near-infrared reflectance spectroscopy is a secondary method: The
instrument first has to be calibrated with samples analyzed by the st
andard method. Sixty-three stool samples with known fat content (range
4.79-292.5 mg/g), 24 samples with known nitrogen content (range 5.36-
19.38 mg/g), and 24 samples with known water concentration (range 60.1
-82.22%) served for calibration, A further 69 samples were analyzed to
validate the procedure. Results: There was a satisfactory correlation
between the measurements produced by near-infrared reflectance spectr
oscopy and those produced by standard methods: fat r = 0.97; nitrogen
r = 0.94 water r = 0.96. Conclusions: Near-infrared reflectance spectr
oscopy appears to be a reliable, simple, and rapid method of measuring
different fecal components-as precise and accurate as the standard me
thods. Stool samples should be analyzed immediately after collecting o
r stored only a few days before analyzing. (C) 1997 Lippincott-Raven P
ublishers.