For detection of SP-D and
cotinine in plasma, enzyme-linked immunosorbant assay (ELISA) was carried out using the enzyme-linked immunosorbent kit (Glory Science, Del Rio, TX78840, USA) in the UHS Laboratory of Physiology and Cell Biology, Lahore.
Second, serum
cotinine levels reflect recent exposure; thus, exposure misclassification might have occurred.
A urine
cotinine threshold value (ng/mL) below 10 was considered 'no exposure,' a value of 10-500 was considered as 'passive smoker,' and a value above 500 was considered as 'active smoker.' A urine cotinine/creatinine ratio of 30 and below was considered as 'no exposure' and a value above 30 was considered as 'passive smoker' (17, 18).
Because of the slow elimination of
cotinine, several CM smoking programs have initially reinforced abstinence using daily breath CO monitoring and then transitioned to less frequent monitoring with
cotinine measures (e.g., Dunn et al, 2008; 2010; Heil et al., 2008; Higgins et al., 2004; 2007; 2010).
adult ([greater than or equal to] 18 y old)], sex, race/ethnicity, smoking status (current, former, never), and
cotinine level [10 ng/mL cut point; a threshold that has been associated with active smoking (Pirkle et al.
Researchers used specially designed hand wipes to extract nicotine from the hands of participating children and took saliva samples to look for corresponding levels of
cotinine. All of the children had detectible nicotine levels on their hands and all but one had detectable
cotinine in saliva.
The
cotinine creatinine ratio (CCR) of each sample was calculated from the equation CCR = urinary
cotinine (ng/ml)/urinary creatinine (ng/mg).
In the 1980s, children had an average of 0.96nl/ml of
cotinine in their saliva, while in 1998 this had reduced to 0.52nl/ml.