Frequently asked questions (FAQ)

What does the KPMP hope to do?

The KPMP hopes to make precision medicine possible for kidney diseases. KPMP will help scientists understand the kidney at a very detailed level.  KPMP scientists will make a map of the kidney to show important cells, regions, and disease pathways. Ultimately, KPMP research will find new markers and treatment targets that make personalized, effective, and safe treatments possible for kidney diseases.

What is chronic kidney disease (CKD)?

CKD means that the kidneys have become damaged over time, and they can’t filter blood like they should. This damage can cause wastes to build up in the body. CKD may get worse over many years and lead to kidney failure. Kidney failure is sometimes called end-stage kidney disease.

What is acute kidney injury (AKI)?

AKI is a sudden and short-term loss of kidney function. But, AKI can harm the kidneys and lead to CKD over time.

What is a kidney biopsy?

A kidney biopsy is when a doctor takes out a small piece of the kidney to look at under a microscope. The doctors who perform kidney biopsies are nephrologists (kidney specialists), interventional radiologists (specialists who perform procedures using imaging equipment), or surgeons (specialists who perform operations). A pathologist (a doctor who specializes in diagnosing diseases) examines the kidney tissue in a laboratory. The tissue is studied to understand how the kidney has been damaged, and what disease process could have caused that damage, so that appropriate treatment can be chosen.
In the KPMP, scientists will use the kidney biopsies to find new information about the mechanisms leading to acute and chronic kidney diseases. These studies will help doctors know the best way to treat a person’s kidney disease. The knowledge from this research will help answer important questions for people with kidney disease, such as:

  • What type of kidney disease do I have?
  • What will happen to me?
  • What can I do about it?

What are the benefits and risks of a kidney biopsy?


The kidney biopsy shows kidney injury. From a biopsy, the type of injury can be determined, as well as how extensive the injury is and whether the injury is likely to get better or continue to progress. The kidney biopsy will also help KPMP scientists create new tests to understand kidney disease. The tests will dive deeply into kidney cells, and spaces in-between cells, to create a “map” of the kidney. This map will help scientists find new genes, gene products, proteins, metabolic products, and other clues that will indicate how the kidney got injured and what may be done to repair the injury.


Because a kidney biopsy involves putting a needle into the organ which cleans the blood, the most common complication is bleeding. Based on data published in the scientific literature, the overall rate of any bleeding complication is 12.5% or about 1 out of every 8 kidney biopsies. Most often, this is having blood visible in the urine (occurs in 1 out of every 25 kidney biopsies) or developing a swelling of blood (a bruise) next to the kidney (occurs in 1 out of every 10 kidney biopsies). Sometimes, people need a blood transfusion after kidney biopsy because of the bleeding (occurs in less than 1 out of every 50 kidney biopsies). Rarely, people need a procedure to stop bleeding (occurs in about 1 out of every 140 kidney biopsies). After a biopsy, people are asked to rest for a few hours and are monitored closely for any bleeding complications.

Infection is very rare after a kidney biopsy. Less than one out of every 200 people get an infection from a kidney biopsy. To treat infections, doctors typically prescribe medicines called antibiotics to fight the bacteria that are causing the infection.

Death related to kidney biopsy is exceedingly rare, but has been estimated to occur in 1 out of every 2,500 kidney biopsies.

How is the KPMP working to minimize kidney biopsy risks in study participants?

All kidney biopsies will be done by experienced doctors, nephrologists (kidney specialists), interventional radiologists (specialists who perform procedures using imaging equipment), or surgeons (specialists who perform operations) at the KPMP recruitment sites. The biopsies will be performed either with ultrasound to image the kidney throughout the procedure or direct view of the kidney for patients undergoing surgery. Patients who have had prior bleeding problems or other conditions that put them at higher risk of bleeding will not be eligible to participate.

What happens to the kidney sample?

In the KPMP, a pathologist will look at the kidney sample to look for signs of kidney disease. Then, the kidney sample will go to the KPMP research sites where scientists will study the tissue samples to better understand the structural and molecular make-up of CKD and AKI. This understanding will be used to create a “map” of the kidney that will help scientists find unusual genes, gene products, proteins, and other abnormal findings that could indicate the presence CKD or AKI. In addition, any clinically relevant biopsy results will be returned to the patient.

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