Graham Cope

A simple near-patient test for nicotine and its metabolites in urine to assess smoking habit

We describe a disposable, near-patient urine test to monitor cigarette smoking. A plastic device contains the sealed dried reagents to measure nicotine and its metabolites, by a colorimetric assay. The device can be used to give a qualitative assessment of tobacco consumption, simply by observing a colour change. Alternatively, the test can be quantified by measuring the light absorbance with a simple colorimeter, and a concentration of nicotinic metabolites obtained with reference to a cotinine standard. A correction factor for the concentration of the urine sample, based on light absorbance, allows the result to be expressed as a ratio to urine concentration. This method correlates with reported daily cigarette consumption (r = 0.69, p < 0.0001) and compares favourably with cotinine, as measured by gas chromatography (r = 0.89, p < 0.0001). The method provides a simple-to-use, inexpensive way to monitoring tobacco consumption in extralaboratory situations.

Effect of incorporating a 10 minute point of care test for salivary nicotine metabolites into a general practice based smoking cessation programme: randomised controlled trial

Abstract Objective To investigate the effect of immediate feedback from a point of care test for salivary nicotine metabolites in promoting smoking cessation and reduction in tobacco use. Design Prospective, operator blinded, randomised controlled trial. Setting General dental practice, London. Participants 100 adult smokers. Interventions Participants completed a questionnaire on smoking, undertook a clinical examination, and received counselling in smoking cessation. Saliva samples were analysed at presentation and at eight weeks for salivary nicotine metabolites using a 10 minute semiquantitative point of care test. Main outcome measures Smoking cessation measured by salivary nicotine metabolite values (scale 0-6), patient feedback on the perceived value of the test (visual analogue scale) in quitting, and reduction in tobacco use. Results A higher smoking quit rate was achieved with the point of care test (23% cases v 7% controls; P < 0.039), and overall tobacco use also decreased (68% cases v 28% controls; P < 0.001). Baseline values for salivary nicotine metabolites did not differ between the groups (cases, mean 4.1, SD 1.3 and 4.3, 1.4; P = 0.51). 87 participants reattended at eight weeks (44 cases, 43 controls). Mean nicotine metabolite values at eight weeks were 2.58 (2.0) for cases and 4.29 (1.8) for controls (P < 0.001). Conclusion Incorporation of individualised personal feedback using a point of care test for salivary nicotine metabolites into a general practice based smoking cessation programme increased quit rates by 17% at eight weeks and reduced tobacco use.

Near-patient test for nicotine and its metabolites in saliva to assess smoking habit

Smoking is a major risk factor for periodontal disease, causing bone and tooth loss. Effective management of many oral conditions requires accurate information about smoking. We describe a disposable, 10-min, near-patient saliva test to monitor cigarette smoking. A plastic device contains the dried reagents to measure nicotine and its metabolites by a colorimetric assay. The device can be used to give a semi-quantitative assessment of tobacco consumption by observing a colour change and comparing it to a reference chart. Alternatively, the test can be quantified by measuring the light absorbance with a colorimeter and determining the concentration of nicotine metabolites by reference to a cotinine standard. This method correlates with reported daily cigarette consumption (r=0·62, P< 0·0001) and nicotine yield of cigarettes smoked (r=0·35, P<0·01) and compares favourably with cotinine, as measured independently by radioimmunoassay (r=0·57, P<0·005). The method provides a simple-to-use, inexpensive way of monitoring tobacco consumption in dental surgeries.

Point-of-care test to monitor adherence to anti-tuberculous treatment

Background: In the fight against the global tuberculosis epidemic, it is essential to ensure that patients adhere to the treatment prescribed. As the treatment is given for a minimum of 6 months it is common for patients not to take their drugs regularly. Strategies are therefore needed to assess adherence to treatment. One established method is to examine the patients urine for the presence of drug metabolites. A rapid point-of-care test would overcome some of the drawbacks associated with currently available methods. Method: A rapid, safe point-of-care test for isoniazid metabolites (IsoScreen, Surescreen Diagnostics Limited, Derby, UK) has been developed and used to help assess adherence to treatment in a busy clinic for tuberculosis patients in South London. Results: Urine samples were examined from 191 patients receiving isoniazid, usually in combination with rifampicin and other anti-tuberculous drugs. Isoscreen was positive in 93.2% of patients, suggesting that 6.8% might be poorly adhering to treatment. By contrast, examining the same urine samples for evidence of rifampicin ingestion gave positive results in only 43.5%, due to the fact that this test is only positive for a few hours after drug ingestion. Conclusion: IsoScreen has been shown to provide a rapid and safe point-of-care test, which contributes to the detection of non-adherence in patients with tuberculosis.

Measurement of nicotine intake in pregnant women--associations to changes in blood cell count.

Self-reported information about smoking is imprecise and subject to bias, with accuracy varying according to circumstances. Biochemical assessment gives much clearer indications of the effects of tobacco intake on physiological parameters. As part of a randomized controlled trial, a new point-of-care test for smoking was used as a tool to reduce smoking in pregnancy. Measurements of nicotine metabolites in urine were related to a physiological effect of smoking, notably changes to blood parameters, assessed as a routine part of antenatal care. One hundred and eighty-seven pregnant women attending outpatient antenatal care were initially questioned by a midwife about smoking habits and later questioned by the investigators, during which the test was performed and the results relayed back to the patient. Self-reported smoking habit and cigarette consumption, either reported to midwives or the investigators, were shown to be poor indicators of the effects of smoking on blood parameters. The biochemical assessment of nicotine intake was significantly related to white blood count, haemoglobin concentration, haematocrit, mean cell volume, and mean cell haemoglobin. Red cell count, mean cell haemoglobin concentration, and platelet count were unrelated to nicotine metabolite measurements. We concluded that the new test was a reliable measure of nicotine intake in pregnancy and the results correlated with smoking-related changes to haematological parameters.

A new point of care cotinine test for saliva to identify and monitor smoking habit

To the Editors: We welcome the paper by Caponnetto et al. [1], in which they evaluated a nicotine-free inhalator as part of a smoking cessation programme. In the randomised controlled trial, they found no significant improvement with the inhalator, but further analysis of the data showed a significant increase in cessation rate among those with strong and very strong behavioural dependence as measured by questionnaire. While this was a good attempt to find inexpensive means to improve smoking cessation, we question their methodology to assess smoking dependency and abstinence. Questionnaires such as those used for the Fagerstrom Dependence Score and the Glover–Nilsson Smoking Behavioural Questionnaire are subject to bias and intentional and unintentional under-reporting. Also, smoke topography, the way a …

Serum and tissue antioxidant capacity in cervical intraepithelial neoplasia investigated using an enhanced chemiluminescent reaction.

Depleted antioxidant defence has been implicated in the pathogenesis of cervical neoplasia. We determined the systemic and local antioxidant status of women with this condition. Thirty-four women with varying grades of cervical intraepithelial neoplasia, 25 patients who had been treated successfully with diathermy loop excision, and 56 women who had no evidence of cervical abnormality acted as controls. Total antioxidant capacity of serum and protein-free serum, and of neat and protein-free homogenized cervical punch biopsies were determined using enhanced chemiluminescence. Mean serum antioxidant capacity of patients with current neoplasia and treated patients was not significantly different from that of controls. However, mean antioxidant capacity of homogenized cervical tissue from women with neoplasia was significantly lower than control means (P < 0·005), while results for treated patients were intermediate between those from diseased and normal samples (P < 0·05). The enhanced chemiluminescence technique has potential as a suitable method for measuring total antioxidant capacity of cervical tissue, and warrants further investigations using other tissue types. Significant antioxidant depletion in cervical intra-epithelial neoplasia appears to be confined to the local cervical mucosa.

Point-of-care urine test for assessing adherence to isoniazid treatment for tuberculosis

To the Editor: Good adherence to treatment for tuberculosis (TB) is essential, both to cure disease and prevent development of drug resistance. Adherence to chemoprophylaxis (preventive therapy) for latent TB infection (LTBI) is particularly poor [1]. Methods for measuring adherence to TB medication include detecting urine colour change due to the presence of rifampicin. However, this effect is short lived, peaking at 2–6 h and is only seen in <50% of patients [2]. Directly observed therapy (DOT) will ensure adherence to antituberculous treatment, but this can be unacceptable and many patients do not tolerate a three times a week regimen. DOT is costly in terms of personnel and is seldom employed in chemoprophylaxis patients [1]. The highly reliable Arkansas method for detecting isoniazid metabolites in urine relies on a laboratory colorimetric assay, involving adding drops of prepared solutions of reagents, including potassium cyanide, to a urine sample [3]. There are obvious risks involved in handling and storing the reagents. IsoScreen (GFC Diagnostics, Bicester, UK) uses the reagents of the Arkansas Method but in an enclosed plastic testing device (SafeTube; GFC Diagnostics), allowing safe and rapid point-of-care testing in clinics and patients’ homes [2]. The urine colour change is apparent within a few seconds but 5 min is allowed to ensure stable colour development. Purple or blue samples are deemed positive, green intermediate and yellow negative. High sensitivities and specificities have been reported, but without a consistent relationship to the timing of the previous dose of isoniazid or measurement of acetylator status [2, 4]. In this prospective study, we analysed the relationship over time of the colour change seen with IsoScreen over 72 h to determine whether different colours could accurately inform when the last dose was taken, …

Utility of point of care cotinine test during pregnancy

Shipton and colleagues highlight the unreliability of self reported smoking status by pregnant women.1 Their findings reinforce the need for biochemical verification of smoking habit to identify all smokers, who can then be offered advice and support to quit. We used a new 5 minute point of care urine test for cotinine called SmokeScreen to …

Simple colorimetric test to quantify exposure to environmental tobacco smoke: occupational health study

Tobacco smoke is an important environmental contaminant of indoor air. Chronic exposure has been implicated in heart disease and lung cancer in adults and in upper respiratory disease in children. Subjective assessment of exposure, as noted by questionnaires, is dif®cult because of its emotive nature. Therefore, biochemical measurement of biomarkers may provide a more accurate determination of individual exposure. Measurement of nicotine metabolite concentration, such as cotinine, in urine, plasma or saliva is regarded as the approach of choice. A variety of methods are available, such as gas chromatography±mass spectrometry and high-performance liquid chromatography, but they are restricted to the laboratory. Biofeedback about tobacco smoke intake has been shown to be helpful in reducing exposure. To facilitate this feedback we have developed a near-patient test to monitor active smoking using a colorimetric assay to measure nicotine and its metabolites incorporated into a disposable plastic enclosure. We have used this to monitor active smoking in pregnancy and cardiovascular disease. We recently modi®ed the reagents to improve sensitivity to detect nicotine metabolites in saliva in order to develop a chair-side test to monitor smoking in dental practice. Our aim was to determine whether this test could detect exposure to environmental tobacco smoke and to assess whether exposure in an occupational setting correlated with known physiological effects of passive smoking.