Factors that Can Affect the Accuracy of Your Blood Test Results

According to the World Health Organization, chronic diseases kill millions of people each year.

Diabetes alone accounted for nearly 1.6 million deaths in 2015. Deaths caused by neurodegenerative diseases such as dementia doubled since 2000, and this number is expected to grow in the upcoming years.

Although these are alarming facts, you might be happy to find out that numerous diseases and injuries, particularly chronic illnesses, can be prevented.

To prevent a disease, you first need to be aware of it.

To be aware of it, you need to do the right thing and get your health checked periodically.

Discovering a predisposition to the disease earlier on gives you a massive advantage. You’ll be able to follow special treatments and minimize its risks or eliminate them.

But how to get tested for various diseases which might affect you?

Well, one of the simplest and most efficient ways is by using direct-to-consumer labs. These are usually discount labs you can purchase online at affordable prices and have your general health checked in a matter of days. No doctor visit is required so that you can quickly check your blood tests and monitor your health if you are an educated patient.

However, you need to keep in mind that there are many factors which can influence the results of your lab tests. In other words, these factors can reduce the accuracy of your results, and that’s why you need to follow up the doctor’s advice before drawing blood for testing.

This article is going to offer you a broader understanding when it comes to factors which influence lab tests. Keep reading to learn more about your health and how you can optimize the results of your lab work investigations.

1. Biotin

Biotin is also known as vitamin B7 or vitamin H. This is a coenzyme the body needs for different metabolic processes. For example, the body needs biotin to optimize the metabolism of fat, carbohydrates, and protein.

At the same time, biotin is also needed for the production of certain hormones. You can find biotin in fish, eggs, meat and certain vegetables such as spinach and broccoli. However, you can also take biotin supplements if needed.

Adults need about 30 micrograms of biotin per day. Having more biotin in your system is not a problem, but it might affect some lab tests you make. For example, it can interfere with the results in certain blood tests, which might lead to an incorrect diagnosis of various health ailments.

Biotin Uses and Supplementation

As mentioned earlier, biotin is present in various pills and supplements you can buy online. For example, biotin can be used for treating alopecia, which is a health condition that makes people lose their hair. Doctors prescribe a dose of 5,000 to 10,000 micrograms of biotin per day to treat such health problems.

At the same time, biotin can also be prescribed to pregnant women to support the healthy development of the baby. There are studies performed by researchers at various universities which prescribe large biotin doses to treat various problems with the nervous system.

For example, multiple sclerosis might be treated with around 300,000 micrograms of biotin per day. Some people also use biotin to treat nail and skin problems since no studies are suggesting that a high amount of biotin can lead to health complications or injuries.

How Biotin Affects Test Results

Although supplementing with biotin can be beneficial for the body, this substance can greatly interfere with test results. The FDA (Food and Drug Administration) mentioned that biotin could alter blood test results and cause incorrect diagnosis for certain health conditions.

It is recommended that you stop biotin supplementation at least 72 hours before offering a blood or saliva sample.

What Are the Lab Tests Which Might Be Affected by Biotin Supplementation?

There are many blood tests which can be affected by excessive biotin levels in your bloodstream. Some of these tests include vitamin D tests, any tests which measure the thyroid hormones in your body as well as tests which look at the FSH and LH hormones.

Troponin is another type of test commonly used to diagnose heart attacks and other problems related to the cardiovascular system. If you’re planning to do such blood tests in the future, make sure you put your biotin supplementation on hold to ensure you get accurate results.

What Supplements Have Biotin?

On top of getting biotin from your foods, this substance can also be taken from various vitamins or supplements available in drug stores.

For example, most multivitamin pills, B-complex vitamins, and coenzyme R have high amounts of biotin in them. Similarly, supplements with vitamin H and prenatal vitamins might also contain biotin.

If you’re taking some supplements for hair growth and skin improvement, chances are that you’re also getting some biotin from those. Look on the labels of the supplements you take and look for “biotin,” “vitamin B7”, “vitamin H,” or “coenzyme R” to see if your pills contain biotin.

If you have been instructed to stop biotin supplementation a few days before your blood test but forgot to do so, make sure that you inform your doctor about it. Your health practitioner needs to know this is the case your results show inaccurate or confusing results.

2. Age

The advancing age of a patient also significantly influences the results of a particular blood test.

In most cases, people of an elderly age tend to receive a higher percentage of incorrect/inaccurate results in comparison with younger adults. That’s because certain hormones and substances in the body are interpreted differently by lab tests as their levels increase or decrease with age.

To give you an accurate example, a lipid panel of an older adult is much different than the one of a young person. The levels of triglycerides, good cholesterol, and bad cholesterol tend to increase with age up to about 55-60 years in males and around 65 years in females. Some studies show that triglyceride levels continue to increase in senior females.

When this happens, doctors don't use reference values based on age anymore because they are inefficient in people of elderly age. Instead, they test the risk of cardiovascular disease and formulate treatment options based on that because this method is much more efficient.

At the same time, there are blood tests which measure the prostate-specific antigen (PSA) levels in men. PSA can increase in people of an elderly age as more PSA gets into the bloodstream and interferes with the test results.

3. Urinary Tract Infection

Another factor that can influence the results of a PSA test consists of urinary tract infections. Various urinary tract bacteria can drastically alter the test results and lead to inaccurate diagnosis.

That’s why it’s a good idea to tell your doctor if you ever had urinary tract infections so he can make a more accurate diagnosis when testing your PSA levels.

4. Prostate Procedures

People who have had prostate procedures done are more likely to receive an incorrect diagnosis when doing prostate tests.

For example, prostate surgery or biopsy, as well as prostatitis, can cause abnormal levels of PSA in the body. These factors can interfere with test results and cause false diagnosis. The doctor will eventually inform you when it's a good time to have a prostate test after you have had done a prostate surgery or biopsy.

5. Bicycle Riding

Some studies have found that riding a bicycle can put a lot of pressure on the prostate, which can increase PSA levels. Therefore, prostate test results can come back with incorrect information, which leads to a false diagnosis.

Another thing that can increase PSA levels is ejaculation since it makes more PSA leak into the bloodstream and affects the test results.

6. Obesity or High Body Weight

Obesity is another health issue that affects the results of various blood tests.

For example, obese men have greater BMI, and they usually have lower PSA concentrations. That's because obese men usually have a larger blood volume where PSA can get diluted. As a result, a prostate test can return false PSA results which affect the diagnosis set by the doctor.

Similarly, obesity can also affect the results of rheumatoid arthritis tests. During those tests, various inflammatory markers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are checked to detect the level of inflammation in the body.

Some studies show that obese people tend to have higher levels of ESR and CRP in their bodies, and this can interfere with the results, leading to false diagnosis.

Buy a CRP Test Here

Another blood test that can be affected by body weight is creatinine (used to assess kidney function). This test result may be artificially elevated in people with higher body weight or lean mass.  Cystatin C may be a better indicator of kidney function in those patients.

7. Medications

Any medication that you might take before doing a blood test can significantly influence the results.

Make sure that you inform your doctor about the pills you take, so he can take that into account when interpreting the results. If it is possible, you can discontinue certain medication (after you have received doctor’s approval) to make sure that your blood tests are more accurate.

There are many types of medications which can influence the results of blood tests, including prostate test, inflammation tests, etc.

For example, nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and naproxen can alter the results of a blood test. Other important ones include blood pressure medication, which is known as thiazide diuretics. Some of the most common medication in this category include hydrochlorothiazide, chlorothiazide, and others.

These medications tend to lower PSA levels and lead to a false diagnosis in prostate blood tests. 5-alpha reductase inhibitors also affect PSA levels. These inhibitors are represented by dutasteride and finasteride, which also decrease the PSA levels by almost 50 %.

Metformin, a popular diabetes drug that is gaining anti-aging interest, can reduce B vitamin blood levels. This fact needs to be considered when testing for B-12 or other vitamins.

8. Biological Rhythms

Various hormones and other substances in the body have significantly different levels at certain moments of the day.

For example, you have different cortisol or testosterone levels in the morning compared with those in the evening. That’s why it’s important to do certain tests at specific moments of the day to ensure the accuracy of the test. Your doctor will usually inform you about that and tell you when it’s the best time for a blood test.

Testosterone blood levels peak early in the morning, usually between 7 am, and 9 am. This time of the day is when a testosterone blood test should be done. Throughout the day, testosterone levels slowly decrease, and by evening, they are about two times lower than in the morning.

The same story goes for cortisol levels as well. The levels of cortisol in your body peak early in the morning, and they gradually decline by 50%-100% until the end of the day.

The time of the month or year is also very important when doing health checkups. For example, getting more vitamin D into your body relies on how much you are exposed to the sun. You can also get supplements with vitamin D if necessary, but sun exposure is one of the best and most efficient ways to get vitamin D.

The levels of this vitamin in your bloodstream need to be interpreted based on the time of the year. For example, it’s normal to have the lowest levels of vitamin D during winter times since that’s when sun exposure is limited.

9. Pregnancy

A pregnant woman can also have different test results in comparison with one who isn't pregnant. Pregnancy can change the amount of blood in the body, influence liver hormones, renal function, and other metabolic processes.

Changes in hormone levels depend on the pregnancy stage, and they are usually compared against reference values. Physicians can give a pregnant woman more information on how to interpret these results and what they should do about them.

10. Food and Water

The foods you eat and beverages you drink can influence the results of blood tests. For example, fasting, restricting calories, or being dehydrated can lead to incorrect test results and false diagnosis.

To give you an example, a diet rich in protein can lead to increased uric acid levels, and this will be shown in various blood and urine tests. Similarly, a diet which is low in carbohydrates can increase the levels of ketones (ketogenic diet). If a person is a vegan or vegetarian, the levels of vitamin B12 in his/her bloodstream will be low.

Some studies have shown that carbohydrates can temporarily decrease testosterone blood levels, so it is important to measure testosterone before breakfast.

Fasting is needed before drawing blood for most blood testing. Patients are usually asked to fast for about 8-12 hours before doing a blood test. Fasting is important when checking lipid levels, blood sugar levels, some hormones, and substances in the body.

Not fasting before a CMP test, for example, can lead to an incorrect diagnosis of diabetes type 2 since glucose can be elevated, which is a life-threatening condition if not treated properly.

The Lipid Panel test (Triglycerides, LDL and HDL cholesterol) also requires fasting.  Failure to do so may cause the triglycerides value to be higher than normal.

For more information about which tests require fasting, read: Fasting Blood Tests - Everything You Need to Know

Dehydration also plays a vital role when it comes to blood testing. It can increase blood test values by decreasing the water content of the blood. It can be seen as an imbalance in sodium and potassium levels and lead to false diagnosis. For example, dehydration can affect albumin levels, blood lipids, creatinine (kidney), hematocrit, and some hormones in the body.

11. Caffeine, Alcohol, and Tobacco

Drinking a lot of caffeine from coffee or green tea can also affect some blood test results. Although more studies are necessary when it comes to caffeine, there is a chance that this substance can alter blood glucose levels and temporarily increase them. Caffeine usually passes through the body in around 5 hours, so its effects are less significant in comparison with other substances. Caffeine can also affect hydration, a factor mentioned above. Last but not least, caffeine can increase blood pressure in some people. The lab technician may be alarmed about your blood pressure before drawing your blood.

Alcohol, on the other hand, has a more significant effect on blood tests, depending on how much is consumed and when. For example, this substance might lower serum glucose levels in people of all ages and increase plasma lactate. These changes can happen, especially if alcohol is consumed 2 or 4 hours before drawing blood for testing.

At the same time, chronic alcohol consumption can lead to other problems such as elevated triglyceride levels, elevated creatine kinase levels, elevated liver enzymes, and increased uric acid. As a result, blood tests can be affected, and the doctor could subsequently give a false diagnosis.

Frequent alcohol consumption can also lead to mineral and vitamin deficiencies, particularly decreasing the B-complex vitamins. This potential B vitamin deficiency is a concerning problem in chronic alcohol abusers since the vitamins in the B complex are responsible for the proper functioning of the brain and nervous system.

Patients are asked to cease alcohol consumption at least 24-48 hours before drawing blood for testing. This period should give the body enough time to process the alcohol consumed and prevent blood test levels from being affected. However, liver enzymes and triglycerides may not return to baseline in that short period.

Another substance of concern is tobacco, which can also have a profound influence on blood test results. Those who smoke cigarettes have higher levels of nicotine in their bodies. As you probably know, nicotine is a drug which can increase cortisol levels and elevate concentrations of fatty acids in the blood. It may also increase hematocrit (red blood cell proportion, part of the CBC panel) since the body tries to produce more red blood cells to compensate for the lower oxygen level it is getting due to smoke in your lungs.

As a result, blood tests can come up with confusing results. Whether cigarette smoking is acute or chronic, it’s detrimental for one’s health, and it can mess up with lab investigations.

Cigarettes also contain thousands of toxins and chemicals which are harmful to the body, including arsenic and cadmium. These can increase the biomarkers of inflammation in the blood and show up in blood tests.

12. Exercise

Physical exercise is one of the most important factors that influence blood test results. Whether you do resistance training, HIIT, yoga, or go for a bicycle ride, this activity could influence some of your blood tests.

For example, after an intense session of exercise, the levels of creatine kinase (CK) in the body are increased. CK can remain elevated for up to a week, and this will be picked up on blood tests.

Different types of exercises can also increase or decrease thyroid hormone blood tests. For example, doing anaerobic exercises can elevate the levels of thyroid stimulating hormone (TSH) in the body. At the same time, anaerobic exercises can also decrease FT3 levels. It is estimated that thyroid hormone levels can be altered for several hours or even several days, depending on the individual and his fitness level.

Marathoners are also highly exposed to have altered hormonal levels before and after completing a run. For example, the levels of glucose, albumin, protein, and bilirubin were measured in professional marathoners 4 hours after a run. All these hormones were increased.

Studies performed on professional football players who train regularly also reveal that frequent exercise can boost immune function. One study looked at the white blood cell count in 31 males who didn’t do any exercise as well as 32 males who were playing football for a year.

The white blood cell count was significantly higher in football players, and this leads to the conclusion that regular exercise can improve the immune response of a person.

In another study performed on marathoners, it has been discovered that regular jogging for long periods can reduce the levels of C-reactive protein (CRP), which is a known marker of inflammation. However, excessive running can increase CRP and other inflammatory markers.

When doctors perform an inflammation panel, they test the CRP levels primarily. They want to determine if the inflammation in the body is chronic or acute. Having lower CRP levels as marathoners do helps them avoid chronic inflammatory diseases.

On the other hand, some marathoners also had high PSA levels after completing a marathon. PSA stands for prostate-specific antigen, and it’s a marker of prostate disease. 2 out of 21 marathoners had increased PSA levels after running a marathon, which might state a problem with the prostate tissue. However, this can be a false diagnosis since vigorous exercise tends to increase PSA levels in certain people.

That’s why doctors recommend performing prostate tests twice if PSA levels are increased as a result of exercise. At the same time, one should wait at least 24 hours after exercise to do a prostate exam to get a more accurate diagnosis.

Last but not least, weightlifting has been shown to result in profound increases in liver function tests in healthy men used to moderate physical activity, not including weightlifting. Liver function tests are significantly increased for at least 7 days after weightlifting. It is important to impose relevant restrictions on heavy muscular exercise prior to and during clinical studies.  

Get Your Health Checked Up Today!

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You should take advantage of that and order your first blood test today. If you don’t know what to start with, check out the popular tests on DiscountedLabs, and explore the multitude of blood panels available. These tests are inexpensive, and they’ll help you get your health under control!