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Common Factors Leading to False Positive Result in Nicotine Test

By : AMIT GUPTA, Date : 02/09/2013

False Positive Test Results

These are confusing words which have a very important bearing on clinical trials and test results. Lets take the example of a Nicotine Urine Test as a test case. In Medical Lexicon as per the dictionary, a False Positive is described as a test result that is incorrect because the test indicated a condition or finding does not exist. Any screening test result that is incorrectly detected. So for example a non-smoker could be diagnosed as a person with a Smoking Problem as a result of a False Positive outcome. This is one of the main complaints of athletes and sportsmen who are declared toxic and unclean based on some adulteration / contamination which authorities do in collusion with the management to disqualify or irretrievably damage the reputation of the subject. These are the machinations which politicised sports body officials resort to in the bad world of sports.


The spillover effect can also be found with Pre-Insurance health checkups where the subject deliberately conceals his smoking or an alcohol drinking habit. A False Negative is a negative test result when the attribute for which the subject is being tested actually exists in that subject or Test results showing no problem when one exists. Its diametrically opposite to False Positive. So for example a smoker gets himself tested using the Nicotine Urine Test but the result absolves him of any nicotine in his system. Both inaccuracies have far reaching ramifications and consequences detrimental to the Insurer or the Principal Company under whose against the test is being conducted.


A urine test can in general produce more false positive tests as compared with other types of assays. For example using a hair follicle for testing nicotine virtually seals the results permanently. There can be very little lee way to manipulate the end result. In the US, no more than 10% of the clinical labs meet the Federal Requirements stipulated and many states do not have a policy of regulation and monitoring as a result of which these Labs could end up having a ratio of 24.75% of their results getting classified as false positives or results where a subject is detected with nicotine addiction when in fact he is clean and de-toxic.


Sometimes the labs outsource a number of the routine tests like urine or saliva keeping only the blood / serum based tests within their precincts. What happens in reality is that this process of outsourcing is done without appropriate vetting as per the Federal guidelines. These cheap and low cost labs do not have trained technicians to decipher the results properly which is why the problem of false positives are on the rise. You could apply the same analogy to the case of false negatives but on a lower level as it requires collusion and manipulation which is a treacherous and legally unsustainable offence.


Lets take the example of poppy seeds which are processed for opium can also be used as an edible condiment e.g. Toppings on bread / bagels etc.Ingesting poppy in any form will generate aberrated results and the subject could be classified as an opium user. Interestingly poppy metabolites remain in the system for many days at a stretch.


What are the Common Reasons that Can Cause A False Positive Test Result ?

Over The Counter Medications : - Common Cold and Cough Medications both in Tablet and Liquid Form such as syrups. Nasal Sprays and asthma prescriptions can cause False Positives. Therefore it is best to specify all types of medications taken in the last 48 hours But many times, labs are so pre-occupied that they themselves are not aware of counter effects in the event of any medical prescription. In fact the only precaution they prescribe is to have the last meal at least 12 13 hours prior to the test.

Some varieties of Foods can result in a False Positive outcome.

Vitamins Tablets can also cause false positive results. We are informed that B2 can cause the lab result to show a positive outcome for THC (commonly called marijuana).

Medicines which are under Prescription especially antibiotics could affect the end result.

Common lifestyle Diseases such as diabetes, liver disease, and kidney infections can result in false positives for the presence of opium.

Ethnic & Genetic susceptibility The gene pool in human beings is a surprising source of generating false positives especially brown skinned or dark skinned individuals have a tendency towards this in the event they are exposed to second hand smoke.