Most people arrive here because a routine test came back abnormal and nobody has explained what it means. Protein in the urine. Blood in the urine. Often both, and usually without a single symptom.
"It's probably a urinary tract infection"
That is what most patients are told, and it is where the damage starts.
Blood or protein on a urinalysis gets attributed to infection. Antibiotics are prescribed. The patient feels fine. Nobody rechecks the urine after treatment, and nobody asks the question that actually matters: did this come from the kidney's filters, or from somewhere lower down?
An infection is a reasonable first thought. It is not a conclusion. And when the finding is glomerular — when the kidney's filtering units are inflamed — the months spent assuming otherwise are months of scarring that does not reverse.
If your urinalysis was abnormal, you were treated for a UTI, and nobody repeated the test afterward, the question was never answered.
Board-certified nephrology at Remix Medical in Houston. Call (713) 597-5131 or book online.
The question a dipstick cannot answer
Where did the blood come from?
Dysmorphic red cells are misshapen — deformed by squeezing through the glomerulus. They point at the kidney. So do red cell casts, which form inside the tubules and are essentially diagnostic of glomerulonephritis.
Normally shaped red cells suggest bleeding lower down: a stone, an infection, an enlarged prostate, a bladder or kidney tumor. That is a urologic evaluation.
A dipstick sees blood. Only microscopy of the sediment sees which kind, and that single observation determines whether you need a nephrologist or a urologist. It requires someone to actually look at the urine under a microscope, which is not what happens in most settings.
| Finding | What it can mean |
|---|---|
| Protein | Damage to the kidney's filters — needs quantifying |
| Blood | Stones, infection, or glomerular disease |
| Protein and blood together | A glomerular disease until proven otherwise |
| Glucose | Diabetes, or a specific kidney-tubule problem |
Proteinuria
Healthy kidneys keep protein in the blood. Protein in the urine means the filters are leaking.
The dipstick detects it crudely. A urine albumin-to-creatinine ratio quantifies it from a single sample.
- Under 30 mg/g — normal
- 30 to 300 mg/g — early kidney damage, where treatment does the most good and nobody feels anything
- Above 300 mg/g — severe
- Above 3,500 mg/g — nephrotic range, often with swelling. Needs prompt evaluation.
Proteinuria is not merely a marker. It independently drives progression and cardiovascular events, and lowering it changes the trajectory. ACE inhibitors, ARBs, and SGLT2 inhibitors reduce it directly.
Fever, hard exercise, and prolonged standing all cause transient protein. We confirm on a repeat sample before concluding anything.
Albuminuria in diabetes
The most sensitive early signal, appearing years before creatinine moves. Annual screening is standard of care in diabetes and is skipped constantly.
Protein and blood together
Particularly with red cell casts, this points hard at glomerular disease — IgA nephropathy, membranous nephropathy, and the rest of the glomerular family, or lupus nephritis.
That combination is more concerning than either finding alone, and it is the one most often mistaken for infection. It frequently warrants a kidney biopsy, and the timing of that biopsy determines how much kidney survives.
What we do
Quantify the protein. Examine the sediment ourselves, under a microscope. Check kidney function, blood pressure, and the serologies that identify autoimmune causes. Image the kidneys.
Then treat what we find, refer to urology when the bleeding is not glomerular, or establish that the finding is benign and simply needs watching.
That last outcome is common. Knowing it with confidence — rather than assuming it — is the entire point of the workup.
An abnormal urinalysis is a question, not a diagnosis. If yours was answered with antibiotics and never revisited, it is worth another look.
Call (713) 597-5131 or book online.