Abstract:
INTRODUCTION: Current clinical diagnostics are based on biochemical,
immunological or microbiological methods. However, these methods are operator
dependent, time consuming, expensive and require special skills, and are therefore not
suitable for point-of-care testing. Recent developments in gas-sensing technology and
pattern recognition methods make electronic nose technology an interesting
alternative for medical point-of-care devices. METHODS: We applied a gas sensor
array based on 14 conducting polymers to monitor haemodialysis in vitro and to
detect pulmonary tuberculosis in both culture and sputum. RESULTS and
DISCUSSION: The electronic nose is able to distinguish between control blood and
“uraemic” blood. Furthermore, the gas sensor array is not only capable of
discriminating pre- from post-dialysis blood (97% accuracy) but also can follow the
volatile shift occurring during a single haemodialysis session. The electronic nose can
be used for both dialysate side and blood-side monitoring of haemodialysis. The pattern observed for post- and pre-dialysis blood might reflect the health status of the
patients and can therefore be related to the long-term outcome. Furthermore, the gas
sensor array was also able to discriminate between Mycobacterium spp. and other
lung pathogens such as Pseudomonas aeruginosa. More importantly the gas sensor
array was capable of resolving different Mycobacterium spp. such as Mycobacterium
tuberculosis, M. scrofulaceum, and M. avium in both liquid culture and spiked sputum
samples. The detection limit for M. tuberculosis in both sputum and liquid culture is 1
x 104 mycobacteria ml-1 and therefore partially fulfils the requirement set by the
WHO. The gas sensor array was able to detect culture proven TB with a sensitivity of
89% and a specificity of 91%. CONCLUSIONS: In conclusion, this study has shown
the ability of an electronic nose as a point-of-care device in these areas.
