9 Things Every Adult Should Know About Blood Tests
It is advised to get blood work done at certain ages to check for any underlying issue. A set of basic tests like blood sugar, thyroid, calcium, and hemoglobin tests should be done at regular intervals to make sure your health is not being affected. As a thumb rule, labs generally diagnose your results as per your age, medical history, family history, and lifestyle.
At Bright Side, we jotted down a few points that doctors and lab technicians generally do not tell you but which you should definitely know.
1. What is “normal” may differ for men and for women.
With the invention of the internet, we now have an open window to the whole wide world and knowledge available from all around the globe. But there is a loophole here. When it comes to blood tests, it is not advised to cross-check or research it on the internet. Each person’s blood test results can differ greatly from those of another person. This is especially true when it comes to comparing between test results of men and women.
For instance, what is a normal CBC count in men may not be normal for women. It is between 5 million and 6 million cells per microlitre for a man, and between 4 million and 5 million for women before menopause.
2. There is a new painless and needleless way of extracting blood coming soon.
If you are among those who dread thinking about getting a blood test done and fear even looking at a needle, there is good news. A new invention that’s on its way is a needleless device that will replace more than 400 million needle blood draws performed each year in the United States as per estimates. This device hasn’t been released yet but is expected to be soon.
It will also allow you to draw your own blood at home without a needle. No healthcare professional supervision is required to use this device and all you will have to do is place the device on your arm. It will automatically extract the sufficient amount of blood in almost the same time as a conventional blood test.
3. Doctors often choose to not tell you the good news.
It is said that “No news is good news.” Doctors especially seem to believe this phrase. Sometimes, when your CBC, diabetes, or thyroid results are fine, the doctors and nurses may not take the initiative of discussing it with you. However, there might be a possibility that your test results are deteriorating.
Thus, it is important that you insist that your doctor compare your blood test results with previous ones to determine if there is any difference.
4. You need to fast for certain blood tests.
A lot of technicians might not mention it, but there are a lot of blood tests that require you to fast beforehand. Depending on the type of test, a person has to fast anywhere from a few to several hours. As a general rule, a fasting blood test means not eating 8-12 hours before the test. However, you must confirm it with the lab technician.
It is also advised not to smoke, chew gum, or exercise before a fasting test.
5. The amount of blood taken depends on the type of blood test.
If you are wondering why the lab person is withdrawing so many samples of blood, there is nothing to worry about. There are many tests for which a slightly higher amount of a blood sample is required. If you have ever noticed, there are different color caps on each sample tube. Each color signifies something.
There are few tubes that have anticoagulant agents inside the tube so that the blood doesn’t clot. Some have preservatives, some have to be kept at room temperature, while some need to be frozen. There are few blood tests for which a blood sample has to be kept under one of the above conditions, thus, more of a blood sample is required.
6. Results mean different things for different age groups.
Most of us know about the difference in blood test results according to age. While there is a different normal range for adults and different for children. For instance, hemoglobin levels vary for different age groups. It is lower for children — 11 to 13 g/decilitre (gm/dl), and higher for adults — 13.5 to 17.5 gm/dl is normal, and it’s 12 to 15.5 gm/dl for adult women.
In a similar manner, cholesterol levels and calcium levels also change as a person ages.
7. A false positive or a false negative can happen too.
Don’t consider all positives as good and negatives as bad results. Just like a false pregnancy test, blood test results can also be flawed. Sometimes, there are viruses that show up in blood tests a bit later. Thus, doctors always advise getting retested if you still feel the presence of the symptoms.
For instance, if you are infected with the Hepatitis C virus, the blood test results may not show anything because you were infected a few months ago. But, you may still feel the symptoms. False positives are also very common for HIV tests. According to U.S. Centers for Disease Control and Prevention, in any community where 1% of the people are infected with HIV, approximately 2 out of 10 tests done will show false positive.
8. Blood test results may vary at different labs.
The fact here is that every lab has a different normal range for various tests as compared to other labs. These depend on the blood withdrawn in the past and on the results. Based on that, they set the reference ranges of different blood tests. Thus, while one lab may tell you that you are fit and fine, the other may ask you to see a doctor.
Also, there might be a difference in test results depending on the time of the day you got tested and if you ate something specific before getting the test done.
9. Results are not always affected by illnesses.
Not all blood test results get affected by any prevalent illness you might have. On the other hand, even eating something sugary, or drinking the night before can affect your glucose test results the following day.
It is thus advised to consult your doctor before getting any blood test done. He can tell you if a certain disease will affect your blood test result or not.
Do you know of any more facts or myths about blood tests? Do share with us in the comments section below.