Microsoft word - application note kidney stones 4-04.doc
APPLICATION NOTES January 2003 Automated Analysis of Kidney Stones
requires a relatively large sample. Infrared
improved this process, but it was still fairly
the advent of computer technology and the
introduction of Fourier transform infrared
constituents (like cystine, cholesterol,
bile salts, hemoglobin and protein); and
process required grinding a small (1-6 mg)
amount of KBr, then compressing that into
provide important diagnostics a pellet to be analyzed by IR. information.
When ARUP began doing calculi analysis around 1985, stone volume averaged 10 per week, done by two technologists who also did many other departmental tests. Last year (1996), the average sample volume increased to more than 50 each day, six days per week, while personnel had only increased to three technologists who were also responsible for performing other complicated and time consuming tests. Recent addition of an assistant responsible for making KBr pellets improved the situation slightly, but did not
resolve all the problems. It was obvious
that we needed to look for other solutions
The AutoDiff accessory is mounted in the FTIR spectrometer. The FTIR is set to 8 cm-1 resolution and 32 scans. The spectra are collected from 4000 to 400 cm-1 (the same range which is traditionally used by transmittance methods). The achieved time savings are substantial. By KBr pellet method, it took about 3 hours to get 50 samples from container to pellet, and about 2 hours to scan and print data for all of them. With the automated diffuse reflectance accessory, it takes about 2 hours to get a run of 50 samples from container to a
describing, weighing, crushing, separating
Fig. 2 AutoDiff with the Motor
layers and/or colors, as well as mixing the samples); then, it takes about 1 hour to
Control Unit
Our search concentrated on diffuse reflectance - a fairly promising technique, where the light reflected from powder-sample mix is analyzed directly instead of being transmitted through a pellet. Going to diffuse reflectance eliminated the whole step of making a pellet. In addition, this technique offered us the ability to fully automate collection of spectra, data analysis and processing steps. The PIKE
Fig. 3 Spectra of MAP, Uric Acid and Cysteine
medically important. However, additional
pellets and the individual scan-and-print
studies may prove otherwise and may lead
to better diagnostic information). We also
identified spectra and automate our data
them are not consistent with calculi This article has been written and printed with permission of Teri Wojcik of ARUP. Teri is responsible for calculi analysis in the Catecholamine and Vitamins Department. ARUP is an osoteric laboratory located in Salt Lake City, Utah. Within the Metabolics Department, about 1600 calculi are analyzed each month.
APPLICATION NOTES 
The AutoDiff accessory is mounted in the FTIR spectrometer. The FTIR is set to 8 cm-1 resolution and 32 scans. The spectra are collected from 4000 to 400 cm-1 (the same range which is traditionally used by transmittance methods). The achieved time savings are substantial. By KBr pellet method, it took about 3 hours to get 50 samples from container to pellet, and about 2 hours to scan and print data for all of them. With the automated diffuse reflectance accessory, it takes about 2 hours to get a run of 50 samples from container to a
describing, weighing, crushing, separating
Fig. 2 AutoDiff with the Motor