Long gone are the days when you had to march to your local GP surgery to get your blood tested; now, plenty of companies offer at-home testing for those looking to learn more about their hormones, immune system and overall health.

But as anyone who’s done one of these at-home tests will know, the whole process isn’t as simple as you might hope. While most of the tests involve pricking your finger, you’ll often need more than a few drops of blood to fill the vial you’re provided with, which can be tricky if you don’t know what you’re doing. 

So, to help you make the most of these tests, we asked the experts to explain how they work and share their top tips for collecting the all-important blood with ease. 

There are two stages to a classic finger prick blood test: collecting the blood and having it tested in a lab. The first stage is the part you’ll need to do at home by yourself.

“Finger prick blood tests work by collecting blood from the tiny capillaries in the tip of the finger, without needing a venous sample from further up the arm,” says Dr Babak Ashrafi of Superdrug Online Doctor.

“It collects a smaller amount of blood [than a traditional, venous test] and therefore limits the type of tests that can be conducted via this blood retrieval procedure.”

That said, finger prick tests can be used to test several key biomarkers, including your liver and kidney function and hormone levels. 

If you want to make your experience as stress-free as possible, preparation is key.

In some cases, you’ll need to take your sample at a specific time of day. But if a time is not stated, Dr Natasha Fernando, medical director for the home blood test provider Medichecks, recommends carrying out the test in the morning.

“It’s best to take your blood sample in the morning as this is when hormone levels are highest, so your sample will give the best results,” she says. “If you need to fast before taking your blood test, then it’s often easiest to fast overnight while you’re sleeping.”

If you’re worried about getting blood out, waiting an hour or so after you wake up before you take your sample can also help so you have time to increase your blood flow. You can do this by drinking plenty of water or increasing your body temperature with light exercise or a hot shower.

Just before you do the test, make sure to lie out all your kit on a clean, flat surface and wash your hands – you don’t want to contaminate your sample with any rogue bacteria. 

To start collecting your sample, use the provided lancet to prick your finger. Blood should then start appearing on the tip of your finger, which you can transfer into the vial.

“If you’re struggling to withdraw any blood, try massaging the tips of your finger in a downward sweeping motion to encourage blood flow,” Dr Ashrafi suggests.

“Try not to squeeze your finger too hard when trying to extra the blood or scrape your finger on the edge of the tube as this could result in the blood sample being haemolysed, which means that the red blood cells have burst or broken down. This means the sample is damaged and cannot be analysed.” 

Some other tips you can try to increase blood flow include warming your fingers and hands, standing up with your arms below the level of your heart and swinging your arms while clenching your fists.

The finger you choose to prick – and where you prick on the finger – can also make a difference, Dr Fernando adds. “The best finger to get blood from is your ring finger,” she explains. “When performing a finger-prick test, use the side of your ring finger. This is where circulation is at its peak, so you are more likely to collect a complete sample.”

Once you’ve collected a full sample (make sure you’ve filled it up fully to the required volume, as failing to do so can make it hard for the clinicians to test your blood in the lab), make sure to click the lid of your sample shut, give it a swirl around to mix it up and then follow the rest of the instructions in your kit.  

Images: Getty