Plain language
What does a nephrologist do?
Someone told you to see a kidney doctor and you left the appointment without a clear idea of why. That's an extremely common way to end up here.
The short answer
A nephrologist is an internal medicine physician who did additional fellowship training in kidney disease. They handle kidney function itself: how well your kidneys filter, why that changes, blood pressure, the salt and mineral balance your kidneys control, and dialysis when it becomes part of the picture.
The training is long — medical school, then a residency in internal medicine, then a nephrology fellowship on top. That last part is why a nephrologist sees things in a lab panel that a general physician reasonably wouldn't stop on.
A nephrologist is not a urologist
This is the single most common mix-up, and it sends people to the wrong appointment.
A urologist is a surgeon who works on the plumbing — the ureters, the bladder, the prostate, kidney stones that need removing. A nephrologist is a medical doctor who works on the filtering — kidney function, blood pressure, electrolytes, dialysis. Neither does the other's job.
If your problem is a stone that needs to come out, that's urology. If your problem is a number on a lab report, or protein in your urine, or blood pressure that won't behave, that's nephrology.
What we actually treat
Chronic kidney disease at every stage, from a first flagged lab result through advanced disease. High blood pressure that hasn't responded to the usual treatment. Kidney disease caused by diabetes. Protein or blood in the urine. Potassium, sodium, and mineral imbalances. Sudden kidney injury, often while someone is in the hospital. And dialysis — choosing between the types, preparing for it, and the ongoing physician oversight once it's underway.
Why someone gets sent to one
Most people arrive one of three ways. A routine blood test came back with an eGFR below 60 or a creatinine above the normal range. A urine test found protein or blood. Or blood pressure has stayed high through three or more medications.
A smaller group arrives after a hospital stay where their kidneys took a hit, or because diabetes has reached the point where the kidneys need watching by someone who does only that.
None of those are emergencies by themselves. All of them are worth an appointment.
What happens at the first visit
It's a conversation and an examination, not a procedure. Your nephrologist goes through your medical history, every medication and supplement you take, your blood pressure, and your lab work — including older results, because the trend matters more than any single value.
Then you talk through what the results actually mean in plain language, and agree on a plan. First visits run longer than follow-ups, so give yourself extra time.
Bring a photo ID, your insurance card, a complete medication list, and any recent lab work or imaging you have copies of.
Other reasons people come to see us
Questions people ask us about this
What is a nephrologist in simple terms?
A kidney doctor. Specifically, an internal medicine physician with extra fellowship training in how kidneys work, why they stop working well, and what to do about it — including high blood pressure, electrolyte problems, and dialysis.
What's the difference between a nephrologist and a urologist?
A nephrologist treats kidney function medically — filtering, blood pressure, electrolytes, dialysis. A urologist is a surgeon who treats the urinary tract structurally — stones, the bladder, the prostate. If your issue is a lab number, you want a nephrologist. If it's a stone that needs removing, you want a urologist.
Do I need a referral to see a nephrologist?
Many insurance plans require one from your primary care physician before they'll cover a specialist visit, but not all do. Call our office at (559) 661-1965 and our staff will check your plan's requirements with you — that's a quick call, and it saves a wasted trip.
When should I see a kidney specialist?
The common triggers are an eGFR below 60, a creatinine above the normal range, protein or blood found in your urine, or blood pressure that stays high on three or more medications. Diabetes with any sign of kidney involvement is another. If you're unsure whether your result counts, call and ask.
Does seeing a nephrologist mean I'll end up on dialysis?
No. Most people who see a nephrologist never need dialysis. Seeing one early is associated with slower progression, not faster — the point of the visit is to protect the function you have.
Still not sure whether this applies to you?
Call and describe what your doctor said. Our staff will tell you whether it sounds like something we should see and what your plan requires.
Physicians & Experience
Doctors your doctor trusts
Dr. Sheikh Mohammad Masood, MD
President & Nephrologist
Dr. Sheikh Mohammad Masood, MD, is the founding president of Kidney Specialist Inc. With specialized fellowship training in Nephrology from the LSU Health Sciences Center, Dr. Masood provides compassionate, comprehensive care for patients with complex renal diseases, hypertension, and dialysis needs throughout Madera and the Central Valley.
Credentials, training & hospital privileges
Dr. Mohammed Muhibbulla Siddiqui, MD
Nephrologist & Clinical Specialist
Dr. Mohammed M. Siddiqui, MD, brings deep clinical expertise in nephrology, acute renal care, and hospital medicine to Kidney Specialist Inc. Active in medical research, Dr. Siddiqui specializes in advanced chronic kidney disease management, acute renal injury, and resistant hypertension.