PYDT Blood Drug Testing FAQ

Blood tests, unlike urinalysis, detect the presence of illicit drugs, not inactive drug metabolites. In general, THC only remains detectable in the blood of cannabis consumers for a few hours (though low, residual levels may be detected in chronic smokers for up to 12-24+ hours if more sensitive technology is used). Because of this narrow detection window, blood tests are typically only administered in the workplace post-accident in order to estimate recent cannabis consumption. Therefore, most after-hours consumers have little to fear from a blood screen.

The Blood Test

Having a blood test to determine drug use is not very common, but it is very costly. This test is usually reserved for insurance policies, or if a person is seeking employment where safety issues are mandatory.

To administer a blood test, a sample is taken and sent to a lab to test for drug use.


Blood Drug Screen Detection Period
  • Amphetamines (except meth): 12 hours
  • Methamphetamine: 24 hours Barbiturates (except phenobarbital): 1 — 2 days
  • Phenobarbital: 4 — 7 days
  • Benzodiazepines: 6 — 48 hours
  • Cannabis: 2 days
  • Cocaine: 24 hours
  • Codeine: 12 hours
  • Cotinine (a break-down product of nicotine): 2 — 4 days
  • Morphine: 6 hours
  • Heroin: 6 hours
  • LSD: 0 — 3 hours
  • Methadone: unknown
  • PCP: 24 hours
Looking At Blood Drug Testing? You Are Also Probably Looking At A Urine Drug Test!

Insurance companies agree to take on a certain amount of financial risk when issuing a new insurance policy. A great deal of consideration must be placed on the likelihood that the new customer may get sick or even die. A battery of simple blood test and urine test can reveal enough to make a proper determination of risk. Most insurance companies require applicants to submit blood and urine samples so tests can be conducted to determine whether or not the person's present health status fits a pre-determined pricing model.

Why Both Blood Drug Tests And Urine Drug Tests?

A blood drug test measures the actual amount of drugs in the blood at the time of the test. Unlike the blood drug test, the urine drug test results can not tell whether or not the person was under the influence at the time the test.

Blood Drug Test - The blood drug test is most often to determine the presence of current health issues such as nicotine, diabetes, HIV/AIDS, cholesterol levels, hepatitis and protein levels. Some insurance companies test for or examine other things depending on their own previous customer experience.

Urine Drug Test - The urine drug test is often used to determine use of illegal drugs, as well as prescription drugs and over the counter drugs that might provide an in-site into your health and personal habits. Did you know that more than 250 over-the-counter or prescription drugs can cause you to test positive for various substances in a urine drug test?

Blood Testing for Cannabis

Cannabis can be detected in blood samples for around few days to a month, depending on what they are looking for (pure drug or metabolites), the sensitivity of the test, how long ago you last used, and how much and for how long you were using.

Drug Test Detection Times for Marijuana

How long do drug tests detect marijuana? There is no simple answer to this question. Detection time depends strongly on the kind and sensitivity of the test employed; the frequency, dosage, and last time of use; the individual subject's genetic makeup, the state of one's metabolism, digestive and excretory systems; and other random, unknown factors.

The basic drug test types and their approximate detection times are shown in the table below.

Urine Blood Hair Saliva
Marijuana - Single Use 1-7+ days 12-24 hrs Doubtful Not validated
(0 -24 hours?)
Marijuana - Regular Use 7-100 days 2-7 days Months


The most popular kind of drug test is the urine test, which can detect marijuana for days or weeks after use. Note that urine tests do not detect the psychoactive component in marijuana, THC (delta-9-tetrahydrocannabinol), and therefore in no way measure impairment; rather, they detect the non-psychoactive marijuana metabolite THC-COOH, which can linger in the body for days and weeks with no impairing effects. Because of THC-COOH's unusually long elimination time, urine tests are more sensitive to marijuana than other commonly used drugs. According to a survey by Quest Diagnostics, 50% of all drug test positives are for marijuana.

Explanations of Blood, Hair and Saliva Drug Tests

Blood tests are a better detector of recent use, since they measure the actual presence of THC in the system. Because they are invasive and difficult to administer, blood tests are used less frequently. They are typically used in investigations of accidents, injuries and DUIs, where they can give a useful indication of whether the subject was actually under the influence.

Urine Test to perform a drug test on someone's urine, a sample has to be collected in an examination cup, (often in a controlled environment). For immediate results, the test is performed with a test card. If the test calls for most sophisticated results, the urine is sent out to a testing facility and the results are given after a week or two.

The urine test is very reliable and is performed at most federally mandated facilities that require drug testing.

Hair tests are the most objectionable form of drug testing, since they do not measure current use, but rather non-psychoactive residues that remain in the hair for months afterwards. These residues are absorbed internally and do not appear in the hair until 7-10 days after first use. Afterwards, they cannot be washed out by shampoos (though shampoos may help remove external smoke particles that get stuck in the hair). Hair tests are more likely to detect regular than occasional marijuana use. One study found that 85% of daily users tested positive for marijuana, versus 52% of occasional smokers (1-5 times per week). Ingested cannabis was less likely to be detected than smoked marijuana. It is doubtful whether hair tests are sensitive to one-time use of marijuana.

Saliva testing is a newer, less proven technology. The sensitivity of saliva tests is not well established in the case of marijuana. In theory, they are supposed to detect recent use, but this may range from several hours to over a day. They are supposed to detect secretions from inside the oral tissues that cannot be washed out with mouthwash. Because they are less intrusive than blood or urine tests, the industry has been eager to develop saliva tests. Due to reliability problems, they have yet to gain acceptance in the U.S., but they have come into use in some other countries, such as Australia.