 When
you visit your doctor for a regular checkup it's quite standard that blood
tests are ordered. This is the normal way for doctors to access your health
but most times the results we get look like gibberish. Because tests can be
overwhelming it’s important to ask relevant questions. Here are 10 things
that you might not know to ask.
1. Standard tests to look out for.
A
typical set of tests might include a CBC, a complete blood count, which
measure hemoglobin, and the number of red and white blood cells in your
system. They might also request a basic metabolic panel, also called a blood
chemistry, which looks at the chemical levels in your blood such as blood
glucose, electrolytes, and calcium to check on your organ function. Another
test is called the lipoprotein panel, which looks at the fat levels in your
blood, to check cholesterol.
|
|
2. Doctors focus on the bad news.
Doctors
don’t discuss the good news. If your test comes back without any bad results,
they tend not to contact you. They might send you the test results without
any explanation, which can be difficult for a person who didn’t go to medical
school to understand. It’s a good idea to follow up with a nurse practitioner
or doctor, even if the results came back without any concerns. It’s good to
track if the results differed from your last set of tests and find out what
those changes might mean.
3. Positive and negative are opposites in bloodwork.
 When
it comes to bloodwork, the meanings of these words get reversed. When a test
result comes back positive it means the molecular markers in your blood test
detected traces of the disease, gene or risk factor, which is not good news. When a test result comes back negative, it
means the test did not find anything indicating you have a disease or a
disorder. For example a test looking for DNA markers for the BRCA1 or BRCA2
gene for breast and ovarian cancer risk, you should be hoping for a negative result, indicating you don’t have the gene.
4. Results differ from person to person.
It’s
never a good idea to compare your results to that of others. For example,
what is considered normal for men can be quite different from what normal
looks like for women. If you compared the results of red blood cells in a
CBC, the results will be much higher for men, with 5 to 6 million cells per
microliter, compared to pre-menopause aged women who average 4 to 5 million,
due to loss of blood during menstruation.
5. Age affects the results.
It’s
important to know that results mean different things at different ages, as
normal levels change as you age. For hemoglobin, which is part of the CBC
test, children’s levels are much lower than adults, ranging from 11 to 13
grams per deciliter (abbreviated to gm/dl). For adult men, it should range
from 13.5 to 17.5 gm/dl and women it should range from 12 to 15.5 gm/dl. The
difference is notable. Similarly, cholesterol numbers mean vastly different
things as you age. LDL (Low-density lipoprotein – the bad kind of
cholesterol) levels should be lower than 130 milligrams per deciliters for
most people. Rates of 160 to 190 mg/dl indicate a risk for heart disease. The
risk is higher if you are over the age of 45 for men and 55 for women.
6. False positive test results are quite common.
 Tests
sometimes come back positive when they are not, called a false-positive,
which means a person might think they carry the markers for a genetic
disorder when in fact they do not. The first screening for a condition often
needs to be checked with a more specific second test, to determine whether
the results are accurate. An example is the rapid HIV test, which is not as
reliable as the tests requiring longer waiting periods for the results, which
often produces false positives. In communities with a one percent infection
rate, for every ten true positive results, two false positive HIV rapid test
results are expected.
7. False negatives test results can also happen.
In
other cases sometimes a test fails to detect evidence of a disease or
condition you actually have. An example is blood tests for hepatitis C, where
results come back negative when you were exposed to the virus, and the
disease markers lie dormant in your system. If you think you’ve been exposed
to an infectious disease, it’s always a good idea to get tested a second
time.
|
|
8.
Mistakes do happen.
Although
rare, sometimes mix-ups and mistakes do happen. Lab technicians are human and
despite strict practices to ensure accurate results, errors can happen. On
rare occasions, test samples are switched. Results can also be affected by
how blood samples are handled before being analyzed. For instance if a blood
sample is shaken in the tube, the blood cells can  burst, releasing their contents,
possibly causing the test results to differ.
9. Not all labs are the same.
Don’t
compare reports from different labs. Lab technicians compare your test results
to the range that is considered normal for that laboratory, so their
reference is based on the people previously tested in that lab. Sometimes a
lab will set their own reference range, or use different equipment or tests,
which impacts the results, making one lab’s normal range different to that of
another lab’s. Some tests have set a standardized reference range, such as
the test for blood sugar and the results are universal.
|
|
10. Abnormal results aren’t always an indicator.
If
you get back a test result outside the normal range of the lab’s expected
values leading to a diagnosis. Sometimes this outcome is due to other
reasons. For example if you drank alcohol or ate something before the tests,
this could influence the results. That’s why it’s very important to follow
the lab’s instructions for tests, such as fasting for cholesterol tests, or
drinking water for an ultrasound. If you suspect your outcome was affected by
an external source, it’s important to ask to get retested.
|
