Colorimetric Breath Assay Strip Ratings Compared to Established Assessment Methods

Colorimetric assay strips developed by ALT BioScience (Lexington, KY) have the demonstrated ability to detect volatile and non-volatile thiol compounds in oral fluids. They change color based on the amount of thiols present. Objective: Compare the assay strip's outcomes to sensory evaluation and measures of volatile sulfur compounds (VSCs) in breath gas measured using the Oral Chroma® gas chromatograph (OC) and a Halimeter® (H) sulfide monitor. Methods: 41 subjects provided oral fluid and breath samples. Thiol levels were measured using two assay strips, one maxillary and one mandibular. Sensory scores were rated by two judges. VSCs were measured using the OC® and Halimeter® per manufacturer instructions. Analyses used OJ scores or common logarithms of gas concentrations. Within each color assay rating, means and standard deviations were computed for the measurements from the Halimeter®, Oral Chroma®, and sensory methods. A repeated measures model was used to compare the means of these measurements between the color assay ratings. Results: The mean concentration for total VSCs, as measured using the OC®, was significantly higher for subjects with a 6 to 8 assay strip rating than those with a 1 to 5 rating (p = 0.006). The means (SD) were 338 (498) and 62 (57), respectively. This is similar to threshold ratings for breath odor detection reported in the literature. The mean Halimeter® reading was also higher for the 6-8 assay rating group but did not reach statistical significance [223 (212) vs 108 (89); p=0.295]. OJ scores did not differ between the groups [2.0 (1.4) vs 1.4 (1.3); p=0.967]. Conclusion: Based on these data, the colorimetric assay strip ratings of >= 6 would be a good indicator of detectable breath odor. Further development is needed to improve sensitivity of the strips' comparisons with sensory ratings. Study supported by ALT BioScience, Lexington, KY, USA