ICD-10 Diagnosis Code N21

Calculus of lower urinary tract

Diagnosis Code N21

ICD-10: N21
Short Description: Calculus of lower urinary tract
Long Description: Calculus of lower urinary tract
This is the 2018 version of the ICD-10-CM diagnosis code N21

Not Valid for Submission
The code N21 is a "header" and not valid for submission for HIPAA-covered transactions.

Code Classification
  • Diseases of the genitourinary system (N00–N99)
    • Urolithiasis (N20-N23)
      • Calculus of lower urinary tract (N21)

Information for Patients


Bladder Diseases

The bladder is a hollow organ in your lower abdomen that stores urine. Many conditions can affect your bladder. Some common ones are

  • Cystitis - inflammation of the bladder, often from an infection
  • Urinary incontinence - loss of bladder control
  • Overactive bladder - a condition in which the bladder squeezes urine out at the wrong time
  • Interstitial cystitis - a chronic problem that causes bladder pain and frequent, urgent urination
  • Bladder cancer

Doctors diagnose bladder diseases using different tests. These include urine tests, x-rays, and an examination of the bladder wall with a scope called a cystoscope. Treatment depends on the cause of the problem. It may include medicines and, in severe cases, surgery.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

  • Bladder biopsy (Medical Encyclopedia)
  • Bladder outlet obstruction (Medical Encyclopedia)
  • Bladder stones (Medical Encyclopedia)
  • Cystitis - noninfectious (Medical Encyclopedia)
  • Indwelling catheter care (Medical Encyclopedia)
  • Neurogenic bladder (Medical Encyclopedia)
  • Self catheterization - female (Medical Encyclopedia)
  • Self catheterization - male (Medical Encyclopedia)
  • Urinary catheters (Medical Encyclopedia)
  • Urinary Retention - NIH (National Institute of Diabetes and Digestive and Kidney Diseases)


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Ureteral Disorders

Your kidneys make urine by filtering wastes and extra water from your blood. The urine travels from the kidneys to the bladder in two thin tubes called ureters.

The ureters are about 8 to 10 inches long. Muscles in the ureter walls tighten and relax to force urine down and away from the kidneys. Small amounts of urine flow from the ureters into the bladder about every 10 to 15 seconds.

Sometimes the ureters can become blocked or injured. This can block the flow of urine to the bladder. If urine stands still or backs up the ureter, you may get a urinary tract infections.

Doctors diagnose problems with the ureters using different tests. These include urine tests, x-rays, and examination of the ureter with a scope called a cystoscope. Treatment depends on the cause of the problem. It may include medicines and, in severe cases, surgery.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

  • Injury - kidney and ureter (Medical Encyclopedia)
  • Retroperitoneal fibrosis (Medical Encyclopedia)
  • Ureteral reimplantation surgery - children (Medical Encyclopedia)
  • Ureteral retrograde brush biopsy (Medical Encyclopedia)
  • Ureterocele (Medical Encyclopedia)


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