كيفية التحضير لاختبار الدم

Let's face it, most of us don't enjoy going for a فحص دم, no matter how simple it is. Dr Deborah Lee, of Dr Fox Online Pharmacy, explains how to prepare.

"When you need to have a blood test, it's important to realise that there are many different types of blood tests," she says.

"You will be given specific instructions about your blood test - such as whether you can eat and drink beforehand, or what time of day it needs to be taken. It's in your best interests to follow these instructions carefully because this will affect your results."

Should I eat before a blood test?

If you've been told you need a blood test it's likely you've been told whether it's a fasting or non-fasting test. If it's a fasting blood test, you'll need to avoid eating and drinking - except water - for a period of time before the test is performed. Your doctor will give you this information ahead of the test.

She adds that the most common blood tests can be taken at any time. A good example is a full blood count, which checks the number of red cells, white cells, and platelets.

Why do you have to fast for some blood tests but not others?

To simplify a complicated physiological answer, eating and drinking affects the composition of your blood, which is why some blood tests require you to fast beforehand.

Take, for example, your blood glucose level. When we eat, our body releases a hormone called insulin which lowers our sugar (blood glucose) levels and allows our cells to absorb the glucose for energy.

But that has an impact on the body's usual blood glucose level, so it makes it hard for your doctor to get an accurate reading on whether your glucose levels are in a healthy range. That's why they might ask you to fast beforehand to better understand how your body is dealing with sugars. This is often required to test for السكري.

It's a similar story for other tests that require fasting, as the nutrients you absorb through food and drink can impact the results of your blood test.

Taking medication before your blood test

If you're taking regular medication you should speak with your doctor about whether it will affect your test results.

"In general, you should continue taking your medication as usual if you are having a blood test," Lee explains. "If it needs to be stopped or taken at a different time, your doctor will inform you."

Speak with your doctor before you stop taking these medications or if you are concerned they could affect your blood test results.

Fear of needles

It's not unusual to feel nervous before a blood test. In fact, according to Lee, a fear of needles affects 3-10% of the population.

But if you're not needle phobic and you're just feeling a bit nervous, there are a few things you can do to feel calmer before your test.

Lee says that when you start to feel anxious, this switches on your 'fight, fright, and flight' mechanism - your body thinks it is in danger and is prepared for action.

"You start to feel hot and sweaty with a racing pulse," she adds. "You may have a fall in blood pressure. Your pupils will be dilated. Often people feel light-headed and dizzy - you may feel faint and collapse.

"This is because your sympathetic nervous system (SNS) has swung into action."

The good news is, there are ways to manage it. A التنفس technique called diaphragmatic breathing can help calm your nerves, according to Lee.

"Diaphragmatic breathing means using your diaphragm to fill your lungs," she explains. "If you consciously try to suck in your abdomen, you will be raising your diaphragm.

"Practise this at home, the night before, and the morning of your blood test. You can even be doing it in the waiting room while waiting for your test."

Feeling faint

It's not uncommon to feel dizzy, or even to faint, when going for a blood test. And the issue often gets worse if you're scared of needles. If you do feel dizzy or as if you might faint, it's important you tell your doctor. They can then make you feel more comfortable, or set you up somewhere safe in case you do faint during the test.

Lee suggests focusing on something other than the needle.

"Focus on an object in the room and think hard about that one thing," she advises. "Concentrate on it - focus your mind on this practical thing in front of you and ignore the blood test as much as you can."

If you're someone who is prone to feeling woozy or dizzy once your blood has been taken, it might be worthwhile packing something to eat following the test, provided your doctor says it's OK.

There's a reason you get a biscuit after donating blood - it helps get your blood sugar levels back up and will stop you feeling woozy. Packing a bottle of water or juice can also be helpful to replenish the fluid you lost due to the blood test.