Dear Dr. Toshi, (Lab Results Part 1)
I went to see my doctor, and she showed me my lab results, but I had no idea what they mean. Can you explain them to me?
I'm sure you've had your blood drawn to have lab tests done at the clinic or hospital. But do you know what they're for? Have you wondered what the results mean?
I'd like to give you a quick overview of some of the major blood test results in the next few articles so you can better understand what your doctor is talking about. It would certainly be nice to know what they mean, don't you think? By the way, when your lab values are normal, doctors and other health care providers might say they're "within normal limits," which is good news.
Today, I'm going to talk about a lab called CBC. CBC stands for Complete Blood Count. It's a lab that counts your blood cells, including your Red Blood Cells (RBCs), White Blood Cells (WBCs) and Platelets (PLTs). Those are the major types of cells in your blood. It would be a long article if I covered all of these, so, let's talk about red blood cells today.
You probably know that your red blood cells are the ones that make your blood red. The most important function of the red blood cells is to carry oxygen from your lungs into your body (because your body needs oxygen, of course), and to carry carbon dioxide (a waste product) out from your body to your lungs so you can breathe it out. All the cells that make up your body need oxygen. As you probably know, red blood cells transport the oxygen to your body's cells through your arteries, and they transport the carbon dioxide back from the cells through your veins. So, your blood vessels (arteries and veins) are the roads that go to and from different destinations, red blood cells are delivery trucks, and oxygen and carbon dioxide are the cargo. We have a driver, too, which I'll talk about in a minute. In our lungs, oxygen is loaded into the red blood cells, and then they travel through your arteries and drop the oxygen off at different parts of your body. Then they pick up the trash (the carbon dioxide) and take it back to your lungs where they dump it out and you exhale it to get rid of it. You get the picture.
In each red blood cell, there is a protein called hemoglobin. (The normal ranges are usually about 13 to 17 for men and 12 to 15 for women.) Hemoglobin is like the driver of the car. It contains iron, so you need iron in order to make red blood cells. If you don't have enough iron, your body can't make enough red blood cells, and if that happens you would be diagnosed with "iron deficiency anemia." (We'll talk about anemia some other time.)
Another lab value that's part of the CBC is hematocrit, and it's also important in connection with red blood cells. It's the value that shows how much of your blood is comprised of red blood cells. (It's kind of like a traffic report that tells you how crowded your roads are with red blood cells.) As for the normal values of hematocrit, for males, red blood cells account for about 40-54% of the blood, and for females, it's about 35-47%.
We care a lot about these two values, hemoglobin and hematocrit, when it comes to your red blood cells because if they aren't within normal limits, we need to find out why and fix it to make you well again.
We'll talk about white blood cells next time.
Dr. Toshiko (Toshi) Luckow, MD is a Family Medicine physician at the West River Health Services hospital and clinics.