Yes, your doctor can tell if you smoke occasionally by looking at medical tests that can detect nicotine in your blood, saliva, urine and hair.
When you smoke or get exposed to secondhand smoke, the nicotine you inhale gets absorbed into your blood. Enzymes in your body break down the nicotine into metabolites like cotinine and anabasine, which can be detected by various lab tests.
How long is nicotine detectable in your body?
The amount of time nicotine stays in your body varies from person to person. And since test results may also vary from lab to lab, you should discuss results with your doctor.
Blood
Generally, nicotine stays in your bloodstream for 1-3 days, whereas cotinine can be found up to 10 days after your last smoke.
Saliva
Nicotine and cotinine can be detected in your saliva for up to 4 days after your last smoke.
Urine
Results of a urine test depend on how soon you provide the urine sample after your last smoke:
- If you smoke occasionally, cotinine may be found in your urine for about 4 days.
- If you are a regular smoker, cotinine may be found in your urine for up to 3 weeks.
The amount of cotinine detected also depends on the amount of exposure to nicotine:
- If you have smoked recently, a positive test may be 1,000 ng/mL.
- If you have not smoked in the past 2 weeks, a positive test may be around 30 ng/mL.
Hair
Traces of nicotine can be detected in your hair follicles for up to 3 months. Some advanced hair testing methods can even detect nicotine for up to one year. However, because such hair testing methods are costly, they are not used as frequently as blood, saliva or urine tests.
What factors influence how long nicotine stays in your system?
The length of time it takes for nicotine to get flushed from your system varies depending on your:
- Smoking frequency
- Genetic makeup
- Age
- Hormones
- Liver function
- Lifestyle
- Use of certain medications:
- Antifungals (such as ketoconazole)
- Medication for high blood pressure (such as amlodipine)
- Antibiotics (such as rifampin)
- Phenobarbital
Can at-home tests detect the amount of nicotine in your system?
While various over-the-counter testing kits can use either saliva or blood to tell you whether nicotine is present in your system, they do not provide information on how much nicotine is present.
Since these tests are not as reliable and accurate as the ones used in a lab or doctor’s office, most doctors do not recommend them.
QUESTION
What percentage of the human body is water? See AnswerBenowitz NL. Pharmacology of nicotine: addiction, smoking-induced disease, and therapeutics. Annu Rev Pharmacol Toxicol. 2009;49:57-71.
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Common Medical Abbreviations & Terms
Doctors, pharmacists, and other health-care professionals use abbreviations, acronyms, and other terminology for instructions and information in regard to a patient's health condition, prescription drugs they are to take, or medical procedures that have been ordered. There is no approved this list of common medical abbreviations, acronyms, and terminology used by doctors and other health- care professionals. You can use this list of medical abbreviations and acronyms written by our doctors the next time you can't understand what is on your prescription package, blood test results, or medical procedure orders. Examples include:
- ANED: Alive no evidence of disease. The patient arrived in the ER alive with no evidence of disease.
- ARF: Acute renal (kidney) failure
- cap: Capsule.
- CPAP: Continuous positive airway pressure. A treatment for sleep apnea.
- DJD: Degenerative joint disease. Another term for osteoarthritis.
- DM: Diabetes mellitus. Type 1 and type 2 diabetes
- HA: Headache
- IBD: Inflammatory bowel disease. A name for two disorders of the gastrointestinal (BI) tract, Crohn's disease and ulcerative colitis
- JT: Joint
- N/V: Nausea or vomiting.
- p.o.: By mouth. From the Latin terminology per os.
- q.i.d.: Four times daily. As in taking a medicine four times daily.
- RA: Rheumatoid arthritis
- SOB: Shortness of breath.
- T: Temperature. Temperature is recorded as part of the physical examination. It is one of the "vital signs."
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