A Few Things You Must Know About Hematuria

2025-11-03

Hematuria, as the name suggests, refers to the presence of blood in the urine. According to the latest medical definition, hematuria is diagnosed when three or more red blood cells are visible in a single high-power field (400× magnification) under a microscope. Therefore, it does not necessarily require visible red or pink discoloration of the urine to be considered hematuria.

The appearance and timing of hematuria can help indicate the bleeding site:

Initial hematuria (blood at the beginning of urination) suggests bleeding from the urethra.
Total hematuria (blood throughout urination) indicates bleeding from higher in the urinary tract—such as the kidneys, ureters, or bladder—because blood and urine are mixed in the bladder before excretion.
Terminal hematuria (blood appearing near the end of urination) suggests bleeding from the bladder neck or, in men, the prostate.

Hematuria may be accompanied by urinary symptoms such as painful urination, frequent urination, or a feeling of incomplete bladder emptying. It may also be associated with systemic symptoms such as fever, lower back pain, discomfort in the perineum or lower abdomen, and testicular swelling or pain in men. However, hematuria can also occur without any symptoms, which warrants even greater attention—particularly in men over 40 years old, smokers, or those exposed to occupational chemical agents.

The causes of hematuria can be broadly classified into two categories: glomerular and non-glomerular.

1.Glomerular hematuria may result from:

IgA nephropathy
Post-infectious glomerulonephritis
Membranoproliferative glomerulonephritis
Focal segmental glomerulosclerosis
Rapidly progressive glomerulonephritis
Lupus nephritis
Vasculitis
Thrombotic thrombocytopenic purpura
Drug-induced interstitial nephritis or analgesic nephropathy
Strenuous exercise

2.Non-glomerular hematuria may result from:

Tumors: renal cell carcinoma, angiomyolipoma, hemangioma
Vascular diseases: malignant hypertension, arteriovenous malformations, renal vein thrombosis or infarction, transplant rejection
Metabolic disorders: hypercalciuria, hyperuricemia
Congenital or familial conditions: polycystic kidney disease, medullary sponge kidney
Infections: acute or chronic pyelonephritis, tuberculosis, cytomegalovirus infection, infectious mononucleosis
Other causes: renal papillary necrosis, urinary tract stones, benign prostatic hyperplasia, cystitis, prostatitis, schistosomiasis, coagulopathies, trauma, radiation injury, indwelling catheterization, or certain medications

Because hematuria has numerous potential causes, patients should consult a urologist for a detailed diagnosis and treatment plan.

With advances in modern medicine, both noninvasive and invasive diagnostic tests play important roles:

Urinalysis: to evaluate red blood cell morphology, presence of red blood cell casts, and proteinuria, helping to distinguish glomerular from non-glomerular sources.
Urine cytology: to detect abnormal epithelial cells suggestive of malignancy.
Blood tests: to assess coagulation function, blood disorders, or drug-induced bleeding.
Immunologic tests: such as ANA, complement C3/C4, and immunoglobulin levels, to identify autoimmune causes of renal disease.
Imaging studies: including renal ultrasound, intravenous pyelography (IVP), CT scan, or MRI, to evaluate structural abnormalities of the urinary tract.
Invasive procedures: such as cystoscopy, retrograde pyelography (for patients with poor renal function who cannot tolerate contrast), ureteroscopy, renal angiography, or renal biopsy, may be necessary for further diagnosis.

Because hematuria can have many different origins, any occurrence of hematuria warrants thorough evaluation—especially painless hematuria, which may be an early sign of cancer and should never be ignored. Accurate diagnosis requires a combination of multiple tests and the professional judgment of a urologist. If you experience hematuria or have any related concerns, consult your doctor, who will be glad to provide further explanation and guidance.

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