Blood drug tests aren’t common. However, Google searches on how to pass a blood drug test for weed and other drugs are almost 5 folds as many as those related to urine and saliva drug tests.

The main reason why there so many people looking for ways to pass a blood drug test is that of all the 4 common drug tests, blood screening is seemingly the hardest to beat. For instance, it’s near impossible to use somebody else’s blood or synthetic blood since the specimen is drawn from you at the screening center.

Also, there’s no way you can dilute the drug concentration in your blood- at least none that we know of.

But does that mean that passing a blood drug test isn’t possible? No. Actually, as you’ll soon find out, this could turn out to be the easiest of them all.


Rare Compared To Urinalysis And Swab Test

As we have just hinted, blood drug tests aren’t as common as urine and swab tests. According to OHS Health and Services Inc. (a family-owned corporation that offers drug-free workplace management services), of all the 55 million drug tests that were carried out in the USA in 2008, over 95% of them were conducted using urine specimens. There are a couple of reasons for this.

First, blood drug tests can be very expensive due to the complex equipment and the expertise required. An average blood drug test could cost up to $200. This is a price that not so many employers (and parents) won’t part with easily especially considering that a urine test for the same drug costs as low as $30.

Secondly, while the results from a blood drug test are generally out within 4 days, this wait time could stretch up to 7 days or even 10 days depending on how busy the laboratory is.

Another reason why most organizations opt for urine and swab drug tests is that blood screening is the most invasive since it involves puncturing a vein.

It’s The Most Accurate, Though…

Despite these and other downsides, blood drug screening remains to be the most preferred especially where utmost accuracy is vital.

Blood drug testing is often resorted to when an individual is suspected to be under the influence of a particular drug at that very time. This is because unlike a urine test that looks for the residues of the drug, a blood test detects the actual parent drug before it has been metabolized into its specific end products (metabolites). That’s to say that a positive blood drug test signifies most recent drug use. This is unlike urine or hair drug tests that could detect metabolites from a joint you took several weeks or even months ago.

This method of drug testing is also reserved for people with a history of tampering with the sample. Unlike in a urine drug test where an individual spends some time alone with the sample thereby creating a window for tampering, a blood drug test sample is drawn by the lab technician. As such, you can’t stay with the sample for any length of time.

There’s so much to learn about a blood test and what you need to do to beat one. But let’s begin with what you badly need now.

Likelihood of Being Drug Tested by Ethnicity


How To Pass A Blood Drug Test

Keep Off Drugs

When you consume drugs, they are absorbed into the bloodstream where they hang around for some time before being processed and excreted. Most drugs take several hours to up to a week for the concentration in the blood to subside.

Therefore, as soon as you have been informed of an upcoming blood drug test, you must stop adding more drugs into your system.

This will promote your body’s efforts to detox naturally. Actually, this may be all you need to beat the test.

To pass a blood drug test for weed using natural detoxification, you’ll ideally need at 3-4 days if you are an occasional user.

For regular and chronic heavy users, though, you might want to make this a week as you are more likely to have a relatively higher amount of THC in your blood. If you have more time, abstaining for 2 weeks could be much better.

Use A Reliable Detoxification Product

If you don’t have enough time to detox naturally, your next best bet would be to boost the detoxification process using a reliable detox product.

The reason why I’m emphasizing so much on reliability is that not all of the brands out there work as they claim. So you must go for a brand that has been proven to work.

When sorting out the various detoxification products, consider how long each takes to get you clean. While some work as same-day solutions, others take up to a week to flush the toxins in your system. Also, go through the instructions keenly for any special information regarding its usage.

Even more importantly, ensure that the product does not leave behind any traces that may be picked up by the lab experts and used as proof that you’re trying to cheat the test.

Maintain A Regular Exercise Routine

This method will work if you have around a week to the test. Engaging in some sort of intense exercises will boost your rate of metabolism thereby speeding up the rate at which drug toxins are kicked out of your system.

There are a couple of ways through which exercising helps in passing a blood drug test for weed. First, you probably know that THC is fat-soluble, right? When exercising intensely, your body is forced to tap into its fat reserves as a source of energy. As fat cells are broken down and converted into energy, they release the THC trapped in them which is eventually excreted from the body.

Secondly, when exercising, your body naturally takes in more oxygen. To create more room for the additional oxygen requirement, your body removes the toxin lurking in your blood.

Exercising also increases the circulation of lymphatic fluids throughout the body. One role of the lymphatic system is to speed up the removal of toxins and wastes around the body.

Importantly, you should stop exercising the day before the test. This is because when THC molecules are released from the fat, they become detectable in the bloodstream. You don’t want this to happen on the day of the test.

Use Sure-Jell (Certo)

We listed this method here due to its popularity and to highlight a few things that you should know about it. Note that We don’t vouch for it especially if you plan to rely on it solely. But it can increase your odds of testing negative in 2 ways if combined with another surefire method.

Sure-Jell/Certo is a popular method in passing a urine drug test. It is thought to bind to the lining of the bladder thereby preventing more toxins from getting into the urine.

When used as a method of passing a blood drug test, those who advocate it argue that since Sure-Jell/Certo or any other fruit pectin has some content of fiber, it traps drug metabolites in the stomach and drags them out through poop.

Also, this fiber prevents the reabsorption of drugs and drug metabolites into the bloodstream through the intestinal walls.

It’s true that through the Enterohepatic circulation, drugs do move from the liver to the small intestines via bile juice before being reabsorbed by the enterocyte and transported back to the liver.

It’s also true that taking a lot of fiber has been found to drag some drug molecules through poop. There are a few catches to this method, though. First, it’s not certain how much fiber is in Certo or Sure-Jell. Secondly, there’s no evidence on how much THC actually gets to the stomach through bile.

As such, there’s no way to determine how much fruit pectin you’d need to take to get rid of all the THC in your bloodstream. This is basically a shot in the dark.

All the same, this method might help especially if you ingested the weed. It also involves taking a lot of water which might boost detoxification and thereby increase your chance of beating the test.

When Might You Be Required To Take A Blood Drug Test?

Although blood drug screening is costly, it may be necessary especially when the law calls for it and in situations where lots of money is involved.

An employer may require an employee to take this test, for instance, after an accident at the workplace. This will help in determining whether the accident could be linked to working under the influence.

The United States Department of Transportation also recommends drug and alcohol tests after a road crash.

Drugs That Blood Tests Can Detect And Their Timelines

A blood drug test can detect a wide array of drugs including alcohol. One could also order for a particular item to be screened, though.

Different drugs take varying amounts of time in the blood before they are metabolized into their respective residues and eventually eliminated through urine, poop, sweat, and hair. Here are some of the most common drugs that blood tests look for.


When you smoke weed, THC- the principal psychoactive compound in cannabis- is absorbed into the bloodstream almost immediately. That’s why an individual experiences a ‘HIGH’ within seconds. If you prefer ingesting weed edibles, the time that THC takes to get into the blood may take a little bit longer (30 minutes to 2 hours) before it is absorbed into the blood.

But either way, once it’s in the blood, THC may take 6 hours to 24 hours on average to subside below the detectable levels. If you are a long term, heavy, or frequent user, though, a blood test can pick up traces of THC for up to 2 months after your last dose.


After consuming an alcoholic beverage, it takes 30 to 150 minutes for it to get fully absorbed into the bloodstream after cessation of alcohol consumption. Most of the alcohol is absorbed via the small intestines although a small part of it is also absorbed through the mucous membrane.

Once in the bloodstream, ethyl alcohol- the key active ingredient in alcoholic beverages- can be detected in blood tests for up to 12 hours. This greatly differs from one person to the other depending on the amount of alcohol taken and an individual’s tolerance level.


The effects of meth can last from 6 hours to 12 hours depending on a few factors including an individual’s physical characteristics and the amount of drug taken. The average window within which meth remains detectable in the blood is 24-72 hours.


Cocaine is a fast-acting stimulant effect of which can be felt 3-10 minutes after consumption. Cocaine has a half-life of roughly one hour. This means that one hour after taking it, the concentration in the bloodstream will have reduced by half.

For a casual user, blood tests can pick up small traces of cocaine for approximately 12-48 hours. If you are a chronic and heavy user, this detection window may be much longer since your body can store cocaine in its tissues following heavy consumption.


These are drugs that interact with the opioid receptors in the brain to produce morphine-like effects. While some such as fentanyl are available legally by a medical prescription, others including heroin are illegal.

How long do opioids stay in the blood? The amount of time that these drugs remain detectable in the bloodstream depends on several factors including the specific opioid that was consumed and the individual’s history of consuming that opioid.

Here are some general guidelines that can help predict whether opioids will be detected in an upcoming blood drug test;

  • Heroin: 6 hours
  • Morphine: 12 hours
  • Fentanyl: 12 hours
  • Codeine: 24 hours
  • Hydrocodone: 24 hours


Similar to opioids, Amphetamines are a group of stimulants that work inside the brain to increase cognitive function by accelerating the production of dopamine. Although amphetamines are often prescribed in low doses to help manage depression, obesity, and alcoholism among other disorders, they are also widely available as street drugs/narcotics.

A blood drug test for amphetamines can detect these drugs for 4 to 6 hours. What’s more, these tests can determine whether the drug was taken as prescribed or was abused.

When properly used, the level of amphetamines in the blood plasma ranges from 0.02 to 0.05 ng/ml although it may occasionally be 0.2 ng/ml. Blood concentration levels greater than 0.2 ng/ml are usually a sign of amphetamine abuse.

Factors That Affect How Long Drugs Stay In Your Bloodstream

What I’ve given above are just rough estimates of how long different drugs remain detectable in the blood. However, there are a couple of variables that influence how long a particular drug and/or its metabolites hover around your system. These include:

Metabolism rate: as a general rule of thumb, people with a higher metabolism rate tend to process and eliminate drugs from their system faster than those with a lower metabolism rate. Metabolism has a critical role especially in substances that can be stored in body tissues such as marijuana.

Age: age is not just a number; it also has a dynamic role in determining how well an individual’s organs are functioning. It also speaks volume about a person’s metabolism rate. Generally, younger individuals tend to have relatively better organ function plus a higher metabolism rate compared to older people.

The liver and kidney are the most important organs in processing and excreting drugs circulating in the system. If both or either of these is dysfunctional, then the body will have a relatively harder time flushing out drugs and drug toxins than when these 2 organs are healthy and fully functioning.

Frequency of use and the amount consumed: needless to mention, how much drugs an individual takes in one sitting coupled with the frequency will highly affect the speed at which they will be completely excreted from the system. For a casual user, this may range from an hour to a day. For a chronic and heavy drug user, the drug could be detectable in the blood for weeks or even months.

BMI: Body Mass Index is used to measure body fat in relation to weight and height. The more fat deposits you have in your body, the more drug metabolites can be stored in them. The stored drug compounds are then released back into the bloodstream for excretion. Unfortunately, as they do so, they increase the detection window through blood tests.

There is some good news especially when you are being tested for THC, though. While a blood drug test can detect both THC and its metabolites (THC-COOH), the metabolites are not taken into consideration more so if the main aim of the test was to determine your state of impairment at that time. Only the parental drug matters here.

Passing Probability Calculator

Use the world’s only data-driven marijuana drug test passing probability calculator in order to determine your odds of passing a urine drug test. With over a decade of research and development, this is the only application that can provide an accurate answer to how long cannabis can be detected in your system:

Marijuana Drug Test Calculator

The calculator graphs your Passing Probabilities vs. Days for untampered and diluted/detoxed urine. View Patent US 13/866,015 for more information.

How A Blood Drug Test For Weed Is Done

A weed blood test is used to determine the concentration level of THC in an individual’s blood. Unlike in a urine drug test where the standard cutoff level is 50 ng/ml, blood drug tests are capable of detecting THC levels as low as 1 ng/ml.

Laboratories differ slightly on the medium they rely on when doing a blood drug test for weed. Some use serum or plasma although the proposed legislation recommends using samples of whole blood.

Most of the laboratories used by law enforcement agencies measure the THC concentration in whole blood. To some degree, this could be in your favor since serum and plasma hold twice as much THC as whole blood. So if the THC level in your whole blood is 1 ng/ml, that would be around 2 ng/ml in a plasma/serum test.

If you’ve been scheduled for a blood test, it’s your right to be told what and why exactly you are being tested for. You should also be told how the organization or individual who ordered the test will use the results.

One the day of the test, you’ll be required to go to a laboratory where the blood sample will be taken. A trained lab technician will wrap an elastic band around your upper arm to cut blood flow. This will consequently make the veins swell thereby coaxing them out.

The specialist will then clean the spot where he/she intends to draw the blood from- this can either be the back of the hand or the crook of the elbow. He/she will then insert a sterile needle into the vein and draw a small sample of blood which will be collected either in a vial or test tube before placing a bandage on the punctured site to reduce further bleeding.

The blood sample will then be sent to a laboratory for analysis. Generally, the results should be out in 2-4 days. However, if there are elaborate tests that need to be done or in case there are lots of samples to be tested, it could take 7 to 10 days before the results are back.

What To Do When Preparing For A Blood Drug Test

Open Up About Any Medicines You Are Taking

It’s very important that you tell the lab technician about any prescription medicines, over-the-counter drugs, and supplements that you may be taking. This is because some components in these drugs may cause a false positive for the drugs that you are being tested or other illegal drugs.

Avoid Foods With Poppy Seeds

In addition, immediately after learning about an upcoming blood drug test, it’s in your best interest to avoid pastries and dishes with poppy seeds. These could trigger a false positive for opioids even when taken 2-3 days before the test.

Be Ready For A Urine Test Too

There are instances where you’ll be required to take both a blood drug test and a urine test, for instance, before employment and when applying for insurance. The reason for the urine test is to get to know you much better as far as drug usage is concerned.

Unlike a blood drug test that only detects drugs that you may have consumed recently, a urine test can go back up to a month or 2 or even more. Here’s more information on how to pass a urine test for marijuana.

Understanding The Results

If the results come back negative, then the test did not find any of the drugs you were being screened for in your blood. It could also be that the amount detected was below the established cutoff level which differs between drugs.

If the results are positive, then there are chances that you are screwed. However, it could also be a false positive and further screening may be done to clear out the doubts.

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