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Introduction ⬇

Renal epithelial cell casts are formed from cast-off tubule cells that slowly degenerate, first into coarse and then into fine granular material. Epithelial casts are the rarest.

Urine epithelial cells are of three kinds:

  1. Renal tubule epithelial cells are round and slightly larger than WBCs. Each cell contains a single large nucleus. These are the types of epithelial cells associated with kidney disease. However, the presence of an occasional renal epithelial cell is not unusual because the renal tubules are continually sloughing old cells. In cases of acute tubular necrosis, renal tubular epithelial cells containing large nonlipid vacuoles may be seen. These are referred to as bubble cells. When lipids cross the glomerular membrane, the renal epithelial cells absorb the lipids and become highly refractive. These are called oval fat bodies. Both of these findings are significant and should be reported.

  2. Bladder epithelial cells are larger than renal epithelial cells. They range from round to pear-shaped to columnar. Also known as “transitional” epithelial cells, they line the urinary tract from the renal pelvis to the proximal two thirds of the urethra.

  3. Squamous epithelial cells are large, flat cells with irregular borders; a single small nucleus; and abundant cytoplasm. Most of these cells are urethral and vaginal in origin and do not have much diagnostic importance.

Normal Findings ⬆ ⬇

Renal tubule epithelial cells: 0–3/hpf

Squamous epithelial cells are common in normal urine sample.

Renal tubule epithelial casts: 0 (not seen)

Procedure ⬆ ⬇

Observe the Procedure for Microscopic Urine Examination on pages xxx through xxx of this chapter.

Clinical Implications ⬆ ⬇

  1. Epithelial cell casts are found when they are also present in the urine after exposure to toxic agents or viruses.

  2. Renal tubular epithelial cells are found in:

    1. Acute tubular necrosis

    2. Acute glomerulonephritis (secondary effects)

    3. Pyelonephritis

    4. Salicylate overdose (toxic reaction)

    5. Impending allograft rejection

    6. Viral infections (e.g., cytomegalovirus)

    7. Poisoning from heavy metals or other toxins

Interventions ⬆

Pretest Patient Care

  1. Explain purpose of test, procedure for random urine sample collection, and interfering factors.

  2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Monitor appropriately. Counsel the patient regarding abnormal findings.

  2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.