Very few people decide on their own to see a Nephrologist. Usually a lab report does it for them: a creatinine flagged high, an eGFR that has slipped since last year, or a urine test that found protein. Then comes the question of whether it is worth seeing a kidney specialist, and how soon.

This article walks through the situations in which kidney doctors are usually involved, based on the international kidney guideline from KDIGO, and what a first visit tends to look like. It is general information. Your own results need to be read alongside your history, your medicines and your earlier labs.

Why lab results matter more than symptoms

Kidney disease is common and mostly silent. The CDC estimates that more than 1 in 10 US adults have chronic kidney disease, and that about 9 in 10 of them do not know it. The NIDDK notes that most people in the early stages have no symptoms, which is why blood and urine tests, not how you feel, are what usually raise the question.

Two tests do most of the work. The eGFR, calculated from a creatinine blood test, estimates how well the kidneys filter. The urine albumin-to-creatinine ratio (UACR) looks for albumin, a protein that healthy kidneys keep out of the urine. Our guide to reading eGFR, creatinine and UACR results explains each one, and CKD stages: eGFR and albuminuria shows how the two combine.

The results that usually call for a kidney specialist

KDIGO’s 2024 guideline lists the circumstances in which adults with chronic kidney disease should be referred to specialist kidney care. In plain terms, they include:

  • An eGFR below 30. This is the range where planning ahead for the kidneys becomes part of care.
  • A sustained drop in kidney function. KDIGO names a fall in GFR of more than 20 percent that persists, or more than 30 percent after starting certain blood pressure or kidney medicines.
  • A lot of protein in the urine. A consistent UACR of 300 mg/g or higher, or a doubling of albumin in someone whose levels are already being watched.
  • Protein and blood in the urine together. Our article on blood in the urine covers why that combination gets a closer look.
  • A higher calculated risk of kidney failure. KDIGO suggests referral when a validated risk equation puts the five-year chance of needing dialysis or a transplant above 3 to 5 percent.
  • Blood pressure that will not come down on four or more medicines.
  • Potassium that stays too high or too low. Our guide to potassium levels explains why that matters.
  • Kidney stones that keep coming back, a kidney condition that runs in the family, or kidney disease whose cause is not clear.

The same guideline also lists complications that bring a Nephrologist in: anemia, bone and mineral problems, acid build-up in the blood and poor nutrition linked to kidney disease.

One point surprises people. A single abnormal result is a reason to repeat the test, not proof of disease. KDIGO defines chronic kidney disease as a change that lasts at least three months, and a creatinine can move for short-term reasons such as dehydration. The trend over several results usually says more than any one number.

Situations that are easy to overlook

Some reasons to talk to a kidney doctor do not show up as a red flag on a lab report:

  • Diabetes or high blood pressure that has been present for years. The NIDDK names them as the most common causes of kidney disease in adults. Regular kidney tests are part of good care for both.
  • A long medicine list. Many drugs are cleared by the kidneys, and some can strain them. We cover the common ones in medicines and supplements that can harm the kidneys.
  • A hospital stay with acute kidney injury. Kidney function that dropped suddenly and recovered still deserves follow-up labs afterward.
  • An upcoming scan with contrast dye or a new prescription when your eGFR is already reduced.

What a first visit usually covers

A first kidney visit is mostly a careful review. Expect questions about your blood pressure, blood sugar, family history, past kidney stones and every medicine and supplement you take. Repeat blood and urine tests are common, sometimes with a kidney ultrasound. The goal is to answer three things: whether there is chronic kidney disease, what is causing it, and how likely it is to progress.

For many people the answer is reassuring: stable numbers, a plan to protect the kidneys and a schedule for rechecking. Bring copies of older lab results if you have them. Trends over several years are often the most useful thing a new doctor can see.

When to call a doctor or 911

Call your doctor about a new drop in eGFR, a new albumin result of 30 mg/g or more, swelling in your legs or around your eyes, foamy urine, or much less urine than usual. A sudden inability to pass urine, severe shortness of breath, confusion or chest pain needs emergency care: call 911.

At Legacy Medical, your internist is also a Nephrologist. Dr. Yana Shtern is board-certified in Internal Medicine and Nephrology, labs are drawn in our Palm Beach Gardens office, and members do not need a separate referral for kidney care. Our kidney care page describes how she approaches it. If you have a kidney result you would like explained, a complimentary meet and greet with Dr. Shtern is an easy way to start.

This article is general information, not advice for your situation. Members can call the office with questions about their own care.