Bg. Blijenberg et al., VALIDATION OF A NATURAL URINARY STONE DATA-BASED INFRARED LIBRARY SEARCHING SYSTEM WITH ARTIFICIAL SURVEY SAMPLES, European journal of clinical chemistry and clinical biochemistry, 35(8), 1997, pp. 625-630
In this study we evaluated a Fourier transform IR spectrometer (Bio-Ra
d, USA) equipped with a search system for the analysis of urinary ston
es. We constructed a database of the stone library with the help of re
sults found with X-ray diffraction analysis. In total, we included 223
stone results (213 natural and 10 spurious stones) consisting of sing
le and composite nature. Regarding the latter we used many comparable
and many diverging combinations. Applying 60 artificial referee sample
s that were used in the urinary stone surveys as organized by the Germ
an Society for Clinical Chemistry, we found the instrument hit quality
index alone, as a measure of best spectral match not entirely suffici
ent in relation to acceptable performance. This was also caused by the
absence of some rare components. Of those 60 survey samples, 17 did n
ot meet the guidelines of the survey organization. These guidelines ar
e: qualitatively correct and quantitatively within tolerance limits +/
- 20%. Though a number of these samples seemed irrelevant in a clinica
l setting, they nevertheless represent a challenge for better performa
nce. In the second round, therefore, we included new entries and human
expertise as well, which resulted in an upgrading of the score. We on
ly missed, finally, 4 combinations, mainly related to the purine molec
ule, i.e. uric acid, sodium urate and ammonium urate. In conclusion, b
ased on extension of the library, we consider the search system as acc
eptable. Despite that, human interpretation proved to be necessary.