By Jane S. Davis, CRNP, DNP and Kim Zuber, PA-C, DFAAPA
What blood tests are important in dialysis
If you are new to dialysis, you will see that your blood drawn on a regular basis. It may look like a lot but it is really about ¼ cup (50ml) at the very most. You need to know why the blood is collected and you should keep track of the results to be in control of your care. In this article, we will review lab tests that are done and what the results mean to your health.
Why are they taking all my blood?
You have blood taken weekly, monthly, quarterly and annually. Federal regulations tell the staff what blood tests to do. While the blood is collected at the dialysis unit, it is sent out to get results. That is why you cannot get lab results on the same day. These numbers from your blood tell everyone how you are doing. For example, the dietician uses these numbers to discuss if you need to change what you eat. These numbers tell your whole health care team how well you are doing. If you know what the numbers are and what they mean, you can help with your treatment.
What blood test results you should track and why
While there are many lab tests that are done (weekly, monthly, quarterly, annually), we are going to review the most common. It is always good to keep track of all your test results. Here is a short list of labs to keep an eye out for.
1) KT/V calculation: This will be the most important number to both you and your team. It is a math equation that tells you if we are removing the poisons from your blood with our machines. It takes the urea (the toxic part of the blood that your kidneys are not removing anymore) and by calculating the time on the machine (this is why we encourage you to stay your full time on lab day) and dividing it by your weight, we can figure out if we are doing a good job. Our goal is 1.4 or better. The higher the number, the better the dialysis. You should keep track of your KT/V.
2) Hemoglobin (Hgb): is the number of red blood cells (RBCs) in your body. As you can imagine, this number goes up and down…. especially if you lose blood. The RBCs carry oxygen so if the number is too low, you will be short of breath and everything will make you tired: talking, walking or even eating. Healthy kidneys make a hormone called erythropoietin. This is called EPO for short. EPO tells your body to make new red blood cells. EPO works with iron to make strong, healthy cells. Since your kidneys are not working, they are not making EPO. So, you get EPO (many brands are out there) during dialysis. Your nurse gives it in the IV so you don’t have to take a shot. Same thing with iron. You get iron when your iron levels are low.
3) Ferritin and Iron: You need iron to make new red blood cells. Following the iron saturation (how much iron in your body) and the ferritin tells us if we need to give you iron.
4) Potassium (K): Potassium keeps the heart beating and making sure you have energy. However, if you have too much K, your heart can get into a funny rhythm. K is responsible for the beating of our heart and is essential for your muscles to work. K levels are affected by the foods we eat and certain medications. You can help by watching your diet, many of the foods we eat contain potassium (K), such as bananas, tomatoes and potatoes. Being aware of how much of these foods you eat helps to keep this lab in check. Your dialysis team can also change the dialysis bath to help bring the level back to normal because too much potassium can hurt your heart
5) Phosphorus: Phosphorus is in all the foods we eat and the kidneys are responsible for peeing it off and the GI system for pooping it out. We give binders to take when you eat to ‘bind’ the phosphorus in your diet. Keep an eye on your phosphorus number because it keeps your bones healthy. If your phosphorus is too high, the calcium in your bones moves out of the bones and into the blood. This can cause brittle or easily breakable bones.
6) Vitamin D: Still with the bones….there is oral or IV Vitamin D. We will keep monitoring the entire circle and sometimes tell you we are giving you Vit D orally or by IV. The kidney actually ‘turns on’ Vit D so often we give it ‘activated’ since your kidneys are not working to ‘turn it on’.
7) Calcium: Calcium is in your blood and it can go up or down…. usually opposite from phosphorus but not always. Calcium is found in some foods (mostly leafy green vegetables and dairy), in some of the phosphorus binders and is high in some diseases. It is usually adjusted using the dialysis bath so you should keep an eye on it.
8) Albumin: Albumin is protein in the blood. Because kidney disease and dialysis are ‘inflammatory,’ your body will burn through protein (albumin) faster. We want your albumin to be 4 or more so often the dietician and your whole health team will tell you to eat more protein! In fact, they may encourage you to add protein supplements. This is especially true for PD because it burns through protein faster than hemodialysis.
9) Parathyroid hormone (iPTH): Intact PTH is a big round circle with calcium and phosphorus and iPTH. What is important to know is that if your iPTH is too high, your bones will start leeching out calcium and get too thin and you can break a bone. The dietician always has a wonderful handout of the details of this circle of labs!
10) The serum creatinine that you followed before you started dialysis is no longer important. Because the dialysis machine mucks around with the creatinine, we no longer follow it.
11) Hepatitis B and C: Hepatitis B and C are passed by blood. Since you are around blood at the dialysis unit, we will give you vaccines for Hep B and test you for Hep C. We don’t have a vaccine for Hep C but we do have treatments. Both Hep B and Hep C affect your liver. Since you don’t have good kidneys, we want to make sure your liver stays in good shape.
12) PRAs: PRAs are ‘panel reactive antibodies’. These numbers tell the transplant team if you can match a donated kidney. Higher numbers mean that you are more likely to reject the kidney.
How often are these blood tests taken?
Medicare tells the dialysis units what blood tests to run but doesn’t tell them how often. So, ask your health care team. Sometimes we run extra tests if the first one is a little wacky. Especially since these tests are run off-site and sometime blood gets shaken up in traveling or frozen or heated in the trucks.
Should you be keeping track of your test results?
Yes. We love to share. We love to teach. We love to have you involved. Just ask anyone in your health care team. Your dialysis team includes the doctor, NP or PA, the tech, the nurse, the social worker and the dietician. Any or all of them can explain your lab tests. And we love to have an involved patient!
Who can you ask if you have questions?
Your dialysis team is a great source of information. Additional online resources are listed below. Please also see the Blood Test Results Help Guide in the OneTrackHealth App for more details including references on the recommended test result reference ranges for a person on dialysis.
You can’t make changes if you don’t track your results and know where you need to be. Speak with your nephrologist to confirm the blood test result reference ranges that are appropriate for you.
Track your results today and stay on a healthy track!
· Understanding your dialysis labs Renal Support Network
· Top 15 Calcium-Rich Foods (Many Are Nondairy) Healthline
· Phosphorus, Phosphate Binders & Your Diet One Track Health
· The 2 P’s: P & PTH. What do they stand for and why are they important? One Track Health