Using NicAlert strips to verify smoking status among pregnant cigarette smokers

Background: Decreasing smoking during pregnancy is an important public health priority. An important step towards decreasing smoking during pregnancy is wider dissemination of evidence-based smoking cessation interventions. One such intervention is contingency management wherein mothers earn vouchers exchangeable for retail items contingent on biochemically verified smoking abstinence. Wider dissemination may be possible by using smoking verification methods that require minimal training and equipment. One possibility is to use a cotinine-sensitive dipstick (NicAlert) rather than a bench-top cotinine analyzer, which is expensive and requires relatively extensive technician expertise, or breath carbon monoxide analysis, which is relatively nonspecific. The present study was conducted to begin examining the utility of cotinine-sensitive dipsticks for this purpose.

Methods: Fifty urine samples from pregnant women enrolled in a smoking cessation program were analyzed to compare three different methods for verifying smoking status: NicAlert strips, a bench-top enzyme multiplied immunoassay technique (EMIT) analyzer, and gas chromatography (GC), the current gold standard for determining cotinine levels in urine.

Results: Agreement between GC and NicAlert results were high (96%) and comparable to agreement between GC and EMIT results (94%). Semi-quantitative measurements using NicAlert were low with only 30% of samples in agreement between GC and specific ranges given on the strips.

Conclusions: NicAlert strips appear to be a valid measure of determining smoking status among pregnant smokers although not of absolute cotinine concentration. With minimal training and equipment required, NicAlert strips provide a potentially practical method for using urine cotinine to verify smoking status in community treatment settings.