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Home Health Finger Prick: What is It and How to Prepare It

Finger Prick: What is It and How to Prepare It

A finger prick is a common method used to draw blood samples for testing. It is a much faster way of getting blood samples for either you or the medics.

Over the years, there have been numerous types of lancets created that work differently. Of course, the main goal for each is to collect blood samples effectively for testing.

Conducting a finger prick test can help you know and interpret the different biomarkers present in your body. These biomarkers form the basic characteristics of your blood at a given time. These characteristics are what will help you in turn to understand the functioning of your metabolic system.

Just a few drops of your blood, and you get to have a ton of data on your current health.

Now, the finger prick test is mostly used by people living with diabetes. Often, there is some level of pain associated with it, so I’ll show you how to reduce it today.

But first…

What are finger pricks?

Now, a finger prick is also referred to as finger stick testing. It is a process used to get a small sample of your blood using a device called a lancet.

A finger prick or finger stick differs from others types of blood collection. This is because its main purpose is to target blood only found in the capillaries located at the fingertips.

The sample of blood collected can be later used to test for several things in your body. What is even more amazing is that it does not require high amounts of blood to draw conclusions.

Depending on the type of test you want to perform, you can derive readings for several things.

Just to mention a few, they include:

1. Sugar levels, more so, in diabetic patients

The main compound measured here is glucose. Knowing how high or how low your glucose level is helps you remain afloat with your health.

This is a pretty important test if you are a diabetic.

A fingerstick test can also help you interpret the presence of glycated hemoglobin in your blood. Equated as HbA1c, studying the amounts present in your bloodstream helps reveal your average sugar levels.

Often, the results show your average sugar levels from the previous 2 to 3 months.

2. Checking your liver’s health and inflammation

Some other forms of finger prick testing can help check for the presence of high sensitivity CRP protein. CRP is short for C-reactive Proteins.

These are special types of proteins that get released from the liver into your bloodstream when there’s an inflammation. The CRP molecule has been also attributed as a good indicator for future heart diseases. [1]

Other molecules that may get captured from a finger prick test include AST and ALT enzymes. (Aspartate aminotransferase and alanine aminotransferase respectively)

The presence of these enzymes in your blood may indicate that there is some kind of damage to your liver. They can also occur in the blood when your liver is not functioning properly.

3. To check the levels of fats present in your blood

Different types of fat can get screened in other forms of finger stick testing. Some of these fats include:

HDL (High-density lipoprotein) – HDL is also known as “good” cholesterol because it reduces dangerous fats from your bloodstream. This type of cholesterol helps in the prevention of heart disease.

LDL (Low-density lipoprotein) – LDL fat is the one known as “bad” cholesterol because it accumulates in your blood vessels. As time passes, this accumulated LDL fats form clogs and blockages that impede healthy blood flow. That is why high levels of LDL are often associated with a higher risk of strokes and heart disease.

Triglycerides – Triglycerides are smaller, broken-down versions of consumed fats. They float in your bloodstream and can serve as a source of energy or get stored inside fat cells. Measuring their levels is a good way to check whether fats get metabolized well by your body or not.

Note:

  1. A fat test can also help you find out the ratio of total cholesterol to the total of LDL, HDL, or other types of fat in your blood.
  2. You can also check the ratio of HDL to the other forms of cholesterols in the blood. Higher levels of total cholesterol to the total HDL ratio indicate a higher risk of heart disease.

4. To check your blood count

There are other types of devices using finger prick to determine the blood count in your body. One such device is the OLO analyzer.

This device got clearance from the FDA to conduct Complete Blood Count (CBC) tests.

Despite its small size, it can give you CBC results in a matter of few minutes. The best thing is that it is very cost-efficient but it still works to give you lab-grade results.

The CBC test is a common procedure used in the diagnosis and treatment of people having leukemia. Data obtained from the analyzer can help draw a distinctive line between saving or losing a patient.

Why is finger pricking popular among persons living with diabetes?

People diagnosed with diabetes have to keep detailed tabs on their sugar levels. To achieve this, they use personal glucose monitors and test strips for checking their blood glucose.

Using a finger prick offers a more cost-effective method either when moving or at home. It allows such patients to have this data in real-time.

As a result, they become able to make correct judgments in terms of treatment. It also helps them know whether they need an insulin shot or not.

The finger prick testing can be also done by a qualified medical professional. This is usually seen in some cases where the diabetic patient requires assistance for sugar monitoring.

The only difference is that most lancets used in healthcare facilities tend to be larger.

A larger lancet means that you’re bound to feel a little more pain compared to smaller self-care lancets.

Difference between finger prick and venipuncture

A finger prick differs from the conventional venous blood extraction (also known as venipuncture).

In venipuncture, the blood sample gets retrieved through means of injecting a needle into your vein. This needle comes attached to a syringe that one uses to pull blood out from the targeted vein. It also means that it’s used when one needs more than just a few drops of blood.

Many times, blood from venipuncture have to get stored in tubes for further testing. The red blood cells will get separated from the plasma before the actual screening.

In finger pricks, the idea is to get a small smear of blood onto a test strip. The procedure only targets the thinner blood capillaries found near the surface of your fingertips.

Also, there are no syringes involved, and the blood retrieved doesn’t need storing in tubes.

Types of lancets over the years

There have been several types of lancets developed over the past few years in medicine. However, the 4 most popular ones are:

a. Standard lancets

Standard lancets have protruding blades that plunge into your skin and go up to the capillaries. This plunge can cause pain in varying proportions as the blade may hit some nerve pains.

Normally, standard lancets have a single-use purpose. It means you have to discard them once you’ve used them.

The main reason is that the blades become dull fast and subsequent pricking may cause more pain. Other than that, reusing standard lancets may pose a risk of you developing an infection.

b. Safety lancets

A safety lancet has a springing blade that retracts automatically after making a puncture. This mechanism makes it a more hygienic option as the blade remains covered when not in use. The blade does not dull as fast as seen with standard lancet blades. The covered blade is also not exposed to air, bacteria, or compounds that could build rust on it.

A safety lancet blade is a great option especially if you have a phobia of needles. It gets the work done in a flash and you won’t get to see the blade in action.

c. Vacuum lancets

Vacuum lancets have an in-built vacuum system. This vacuum makes them able to draw blood from shallow depths of the skin. They only go in about 20% deep compared to a standard lancet.

These types of lancets pull blood out from the capillaries using the vacuum without having to dive deep. This mechanism also makes it possible to draw blood from capillaries located in other parts of your body too.

d. Laser lancets

This type of lancets got decommissioned over a decade ago. They worked by collecting blood by boring a hole on your fingertip.

As you’ve probably guessed, it caused much more pain than what we have right now in the field.

How do you do a finger prick blood test? (For sugar testing)

I want to walk you through the process of conducting a finger prick test for blood sugar testing. This will help you even more if you are a beginner.

The steps are:

1. Ready your lancet

The first step is to secure your lancet into the lancing device. If it allows, cock it so that it’s ready for use. (Most manufacturers offer instructions on how to do this for their respective product)

If your device allows, you can also set up the level of depth you want the blade to penetrate.

2. Pick a site to prick on your finger

For sugar testing, the FDA recommends that you use the fingertips. This is even more important when your blood sugar levels keep on fluctuating. [2] It is also great for when you want to calibrate your glucose monitor or pick an insulin dose.

Ensure that you always alternate the fingers and avoid scarred areas.

3. Disinfect the chosen site

Use soap and warm water to wash your hands before using a lancet. Also, ensure that you’ve dried it first to prevent the water from affecting your sugar reading.

4. Prick and upload the blood sample onto the test strip

First, insert an unused test strip into the meter after you’ve turned it on. Afterward, place the loaded lancet on your chosen location and press the launch button to prick the finger.

Ensure that the blood collected can fill your test strip up to the sampling area. Some testing devices may give some form of alert when they get enough blood samples.

Tips for reducing pain from a finger prick

If you’re fretful about the finger-prick blood sample collection, you can use the following tips to reduce the pain:

1. Prick your finger’s side instead

To reduce the amount of pain, you can choose to prick the side of your finger. This is because the sides have fewer nerve endings as compared to the fingertips.

2. Warm your fingers

You’ll get more pain from pricking a cold finger than a warm one.

To warm your fingers, rub your palms together for a while or sit on your hands for a short moment. You can also immerse your cold hands in warm water to get your blood flowing.

3. Always use a new lancing device

A new lancing device comes with a sharper, more accurate blade. A recycled lancet will have a duller blade that may need extra force to penetrate your skin. This results in more pain.

It can get even worse if the blade has traces of rust on it as it can cause serious infections.

4. Stop using alcohol

Using alcohol to sterilize an injection site causes the skin to dry out or even crack. This makes the puncture more painful than it needs to be.

Instead, use basic soap and water to clean your hands. Doing this kills two birds with one stone as it warms and sterilizes the site at the same time.

5. Have you tried the thumb?

Instead of your other fingers, you can also use the thumb as a site for blood sample collection. This is because the thumb has more calluses and will reduce the amount of pain you’ll feel.

6. Don’t squeeze the finger

Squeezing your pricked finger produces further pain. Instead, next time blood droplets don’t form, try dropping your hand to your side for a few seconds and let gravity run its course.

7. Size of the gauge and blade

Some manufacturers make lancets that have small gauges than others in existence. These smaller gauges also have smaller blades that don’t go as deep as longer lancets.

Worth noting though is that the shorter the lancet blade, the fewer the blood sample collected. And the vice versa is also true.

So, you must put into consideration the sample amount needed for the specific test you want.

8. Alternate the prick sites

To reduce pain and let sites heal, you should try changing the puncture locations all the time. This will give other sites time to heal and prevent additional pain next time.

Things that may affect the results from a finger prick testing

There are a couple of things that will affect the data you receive from a lancet test. Should any of them occur, then the overall accuracy of the results may be subject to questioning.

These include:

  • Residue or unclean hands
  • Insufficient blood collected
  • Damaged testing strips

Other factors that tend to skew the results of  finger-prick tests include:

  • The location you pick to collect your blood sample from, e.g., the forearm vs. fingertip
  • Physical conditions like humidity, temperature, and altitude
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