How Do You Know? 

Often, people will ask me how I knew I had Chronic Kidney Disease. I didn’t have any symptoms although I did suffer from high blood pressure, which is the second most common cause of CKD. Well, how did I know then?

When I changed doctors to one closer to my home, she had her own set of thorough tests completed for me as a new patient. One of them was the eGFR [estimated Glomerular Filtration Rate]. She saw that 39% and had me in a nephrologist’s office the next day. The National Kidney Foundation explains why:  

“When your kidneys are working well, they filter out wastes and excess fluid that become part of the urine your body makes each day. When kidneys aren’t working well, you do not remove enough wastes and fluids to keep you healthy. You also cannot make important hormones for your blood and bones. Your GFR number is an estimate of how well your kidneys are working and keeping you healthy. If your GFR number is low, your kidneys are not working as well as they should. Early detection will allow for early treatment. Early treatment may keep kidney disease from getting worse.” 

Remember those old television commercials that announced, “But wait! There’s more.” That applies here, too. In addition to the blood test for eGFR, I needed a urine test. Thank you to The American Kidney Fund for revealing the necessity of this: 

“When your kidneys are damaged, they may let protein leak into your urine. This can be one of the earliest signs of kidney disease. To check for protein in your urine (called proteinuria), your doctor may suggest a urine test. There are two types of urine tests your doctor may use. 

Dipstick urine test 

A dipstick urine test tells your doctor if there is protein in your urine. Your doctor may test your urine in the office or ask you to bring a sample from home. If your first dipstick urine test shows protein in your urine, ask your doctor when you should be tested again. Also ask if a urine albumin-to-creatinine (UACR) test is right for you. 

Urine albumin-to-creatinine ratio (UACR) 

A UACR test tells your doctor how much albumin is in your urine. Your doctor will test your urine to see how much albumin (a type of protein) and creatinine (a kind of waste) are in it. Your doctor will compare these results to figure out your UACR. A normal UACR is less than 30mg/g. If your UACR is more than 30 mg/g, ask your doctor when you should be tested again. Also ask your doctor if you should have an eGFR test.” 

These two tests, the former gold standard for assessing CKD, seem to be falling out of favor. You see, the blood test relies on race as one of its elements. I was taught that was because Afro-Americans have a denser muscle mass. Okay, that seemed acceptable. It also seems that this is no longer acceptable. I understand that racism must be combatted, but what about the science of denser muscle mass? If I’m correct, that’s one of the reasons Cystatin-C is slowly becoming the norm in CKD testing, but certainly not the only one.  

What is Cystatin-C? Let’s find out together. The most easily understood explanation I found was. The Medical Center of the University of Rochester’s

“Your body makes cystatin C constantly, and the protein is found in different fluids, including blood, spinal fluid, and breast milk. When your kidneys are healthy, they filter cystatin C out of the blood so it can be excreted in your urine. 

This is a fairly sensitive blood test to look at your kidney health. Cystatin C can be used to calculate your glomerular filtration rate (GFR). Your healthcare provider can use this to see how well your kidneys are working and if there is a problem. It can also be used to check the progress of your disease, if you have kidney problems.” 

I wasn’t sure enough about this being the best test for CKD, so I turned to Lab Tests Online to see what they had to say. 

“Because cystatin C levels fluctuate with changes in GFR, there has been interest in the cystatin C test as one method of evaluating kidney function. Tests currently used include creatinine, a byproduct of muscle metabolism that is measured in the blood and urine, blood urea nitrogen (BUN), and eGFR (an estimate of the GFR usually calculated from the blood creatinine level). Unlike creatinine, cystatin C is not significantly affected by muscle mass (hence, sex or age), race, or diet, which has led to the idea that it could be a more reliable marker of kidney function and potentially used to generate a more precise estimate of GFR. 

While there are growing data and literature supporting the use of cystatin C, there is still a degree of uncertainty about when and how it should be used. However, testing is becoming increasingly more available and steps are being taken toward standardizing the calibration of cystatin C results.” 

Ah, I see, race need not be taken into account. Hmmm, neither does sex, age, or diet. This almost sounds too good to be true. 

Whoops! I haven’t reminded you what the BUN [blood urea nitrogen] test mentioned above is. My longtime standby, The Mayo Clinic clarifies: 

“A common blood test, the blood urea nitrogen (BUN) test reveals important information about how well your kidneys and liver are working. A BUN test measures the amount of urea nitrogen that’s in your blood. 

Here’s how your body typically forms and gets rid of urea nitrogen: 

Your liver produces ammonia — which contains nitrogen — after it breaks down proteins used by your body’s cells. 

The nitrogen combines with other elements, such as carbon, hydrogen and oxygen, to form urea, which is a chemical waste product. 

The urea travels from your liver to your kidneys through your bloodstream. 

Healthy kidneys filter urea and remove other waste products from your blood. 

The filtered waste products leave your body through urine. 

A BUN test can reveal whether your urea nitrogen levels are higher than normal, suggesting that your kidneys or liver may not be working properly.” 

Considering the information uncovered in today’s blog, I don’t think I’d mind at all if my nephrologist started to use the Cystatin-C method to test my eGFR. How about you? 

Until next week, 

Keep living your life! 

And Then There’s Living Donation

This week just flew by. I guess good news does that. The good news is that this blog is live on Spotify. Just download the free app and enter SlowItDownCKD in the search bar. There we are. Most of the blogs take about seven and a half minutes of listening time. We’re also live on Anchor, Google Podcasts, Pocket Casts, RadioPublic, and Copy RSS. The link is https://anchor.fm/slowitdownckd. Of course, the digital and print books are still available on Amazon.  

Sometimes, kidney transplants are live, too. [How do you like that easy transition to today’s topic?] What do I mean, exactly? I mean the kidney to be transplanted is from a living donor. There’s a separate set of guidelines about choosing a living donor’s kidney than there is for that of a deceased donor.  

By the way, my use of term ‘cadaver donor’ last week created quite a controversy, so I went to a newly discovered site for me, Gift of Life, to find acceptable terms. The one I should have used is ‘deceased.’ My sincerest apologies to those who I inadvertently offended. 

Back to the guidelines for living kidney donation. Let’s find out about them together. First, I’d like to know more about what living kidney donation is. The National Kidney Foundation, my constant favorite source of anything kidney, explains: 

“Living donation takes place when a living person donates an organ (or part of an organ) for transplantation to another person. The living donor can be a family member, such as a parent, child, brother or sister (living related donation). 

Living donation can also come from someone who is emotionally related to the recipient, such as a good friend, spouse or an in-law (living unrelated donation). Thanks to improved medications, a genetic link between the donor and recipient is no longer required to ensure a successful transplant. 

In some cases, living donation may even be from a stranger, which is called anonymous or non-directed donation.” 

Got it. I went to another trusted source, the American Kidney Fund, to find out a bit about what would qualify you to be a living kidney donor. 

“If you want to be a living donor, you will need to have a medical exam with blood tests to be sure you are healthy enough to donate a kidney. Some of the tests needed may include: 

Blood tests 

Urine tests 

Pap smear/ gynecological exam 

Colonoscopy (if over age 50) 

Screening tests for cancer 

Antibody test 

X-ray 

Electrocardiogram (EKG) which looks at your heart 

Other image testing like a CT scan 

You are also required to meet with a psychologist and an Independent Living Donor Advocate to be sure you are mentally and emotionally ready to donate one of your kidneys. 

If you are found to be healthy, and your antibodies and blood type are well-matched to the person getting your kidney, you may be approved to donate your kidney.” 

Who better than the Living Kidney Donors Network to explain why a living kidney donation is preferred over a deceased kidney donation. 

“Kidney transplants save and improve the lives of people with kidney failure. Kidney donation from deceased donors has not been able to keep up with the need for kidney transplants. Over 5,000 people die every year waiting for a kidney transplant.  
Living kidney donation has revolutionized kidney transplantation and is now preferred when compared to a deceased donor transplant. Several benefits and advantages of living donation are now recognized:  

  • Living donation eliminates the recipient’s need for placement on the national waiting list. 
  • Short and long term survival rates are significantly better for transplants from living donors than transplants from deceased donors. (On average, approximately 18 years for a kidney from a living donor compared to 13 years for a kidney from a deceased donor). 
  • The recipients knows the donor, his/her lifestyle choices and medical history 
  • Living donor kidneys almost always start functioning immediately, whereas deceased donor kidneys can take from a few days to a few weeks to start functioning. (Often called a Sleepy Kidney) 
  • Shortens the waiting time for others on the waiting list. 
  • Health deteriorates the longer someone remains on dialysis. 
  • A kidney transplant doubles the life expectancy compared to staying on kidney dialysis treatment. 
  • May be able to avoid being on dialysis 
  • The recipient has time to plan for the transplant 
  • Waiting for a deceased donor can be very stressful and unhealthy. 
  • The surgery can be scheduled at a mutually-agreed upon time rather than performed on an emergency basis. 

Perhaps the most important aspect of living donation is the psychological benefit. The recipient can experience positive feelings knowing that the gift came from a loved one or a caring stranger. The donor experiences the satisfaction of knowing that he or she has contributed to the improved health of the recipient.” 

I wasn’t sure about antibodies although I know what they are and have heard of them in relation to living kidney donors. Johns Hopkins, another source I often turn to, had an explanation I could understand.  

“To test a recipient for these antibodies, a sample of their blood is mixed with a sample of the potential donor’s blood. This test is called a ‘crossmatch,’ and shows how a recipient’s antibodies react with the potential donor’s. Test results can be either positive or negative. It may seem confusing at first, but a positive crossmatch means that a donor and recipient are not compatible. 

A positive crossmatch results in the recipient’s antibodies attacking the donor’s which means the kidney is not suitable for transplant. 

A negative crossmatch means that the recipient’s antibodies do not attack the donor’s which means the kidney is suitable for transplant…. 

If a donor and recipient are not compatible, a transplant can still be performed. Experts at the Johns Hopkins Comprehensive Transplant Center developed a method call plasmapheresis, which helps make a kidney more compatible for a recipient and significantly affects survival outcomes.” 

As you can see from today’s blog, this is a complex matter. We have only touched upon what needs to be involved with a living donor kidney transplant. To further complicate matters, there are two distinct kinds of living donor kidney transplants as UNOS, the site of the United Network for Organ Sharing, tells us: 

“Directed donation 

In a directed donation, the donor names the specific person to receive the transplant. This is the most common type of living donation. The donor may be: 

a biological relative, such as a parent, brother, sister or adult child, 

a biologically unrelated person who has a personal or social connection with the transplant candidate, such as a spouse or significant other, a friend or a coworker, or 

a biologically unrelated person who has heard about the transplant candidate’s need. 

If tests reveal that the donor would not be a good medical match, paired donation may be an option. 

Paired donation 

Sometimes a transplant candidate has someone who wants to donate a kidney to them, but tests reveal that the kidney would not be a good medical match. Kidney paired donation, or KPD, also called kidney exchange, gives that transplant candidate another option. In KPD, living donor kidneys are swapped so each recipient receives a compatible transplant. 

For example, in the diagram above, Barbara wants to donate to her sister Donna, but they do not have matching blood types. Carlos wants to donate to his wife Maria, but they are also not compatible. By ‘swapping’ donors so that Carlos matches Donna and Barbara matches Maria, two transplants are made possible. This type of exchange often involves multiple living kidney donor/transplant candidate pairs.” 

 While today’s blog is longer than usual, there’s still more information we need to know about kidney transplants. There are now 90,872 people [about the seating capacity of the Los Angeles Memorial Coliseum] in the United States awaiting a kidney transplant. That is an astounding number. National Donate Life Month is turning out to be a learning experience for me as well as you. 

Until next week, 

Keep living your life!