Epithelial and Leukocyte Cells in Urine Microscopy

Leukocytes (White Blood Cells)

Neutrophils (PMNs)

• Size: ~12 μm in diameter
• Appearance: Granular spheres with multilobated (segmented) nuclei
• Degenerating forms: Nuclear detail is lost; may be confused with renal tubular epithelial cells. Adding dilute acetic acid enhances nuclear detail.
• Glitter cells: In dilute/hypotonic urine, neutrophils swell and their granules show Brownian movement, giving a sparkling refractile appearance.
• Normal: < 5 leukocytes/hpf
• Pyuria: > 5 leukocytes/hpf - indicates infection or inflammation. > 30 cells/hpf suggests acute infection.
• Clinical significance: Pyelonephritis, cystitis, urethritis, prostatitis. Leukocyte casts + pyuria = renal origin.

Eosinophils

• Not normally seen; > 1% of leukocyte population is significant
• Requires Hansel stain (methylene blue + eosin-Y in methanol), Wright, or Papanicolaou stain for identification
• Clinical significance: Allergic interstitial nephritis (drug hypersensitivity - penicillins), UTIs, renal transplant rejection

Lymphocytes and Mononuclear Leukocytes

• Small lymphocytes normally present in small numbers
• Mononuclear cells (histiocytes, lymphocytes, plasma cells) constituting ≥ 30% of differential = chronic inflammation
• Increased lymphocytes in renal transplant rejection

Epithelial Cells

1. Squamous Epithelial Cells

• Origin: Distal one-third of urethra; in females, also from vagina/vulva
• Size: Large (largest epithelial cells in urine)
• Appearance: Flat, abundant cytoplasm, small round central nucleus, edges often folded
• Staining: Nuclei purple, cytoplasm pink to violet (crystal-violet safranin)
• Significance: Contamination marker; large numbers in female urine suggest vaginal contamination

2. Transitional (Urothelial) Epithelial Cells

• Origin: Renal pelvis to lower third of urethra
• Size: 40-200 μm; smaller than squamous cells
• Appearance: Round or pear-shaped, round centrally located nucleus; occasional binucleate forms; characteristic endo-ecto cytoplasmic rim
• Staining: Dark-blue nuclei, pale-blue cytoplasm
• Significance: A few are normal (desquamation). Large clumps or sheets without instrumentation - requires cytology to rule out transitional cell carcinoma

3. Renal Tubular Epithelial Cells (RTECs)

• Size: 14-60 μm (large, oblong)
• Coarsely granular eosinophilic cytoplasm
• Small nuclei with dense chromatin, rare nucleoli; may be multiple

• Size: 12-20 μm
• Cuboidal or polygonal shape
• Large, slightly eccentric nucleus
• Basophilic endo-ecto cytoplasmic rim

Quick Comparison Table

Practical Tips

• Examine urine fresh - cells lyse within 2 hours at room temperature
• Refrigerate (2-8°C) to preserve cells if delay is unavoidable
• Acetic acid helps differentiate degenerating neutrophils from tubular cells (enhances nuclear lobulation)
• Phase-contrast microscopy improves detection of hyaline casts and translucent structures
• Pyuria in hypotonic urine - use leukocyte esterase strip to confirm (cells lyse rapidly)
• Distinguishing neutrophils from RTECs in degenerating specimens can be aided by the peroxidase cytochemical reaction (neutrophils are peroxidase-positive)

Differential Diagnosis - Silochna, 26F

Summary of Lab Findings

Key Clinical Observations

1. The referring doctor is Dr. Suman Budania (MS) - an MS surgeon, likely a gynecologist/obstetrician in the Bikaner context
2. The TSH report includes pregnancy trimester reference ranges - strongly suggesting this patient is pregnant or recently postpartum

Differential Diagnoses

PRIMARY - Most Likely

1. Pregnancy with Physiological Changes

• TSH of 2.07 fits 2nd/3rd trimester normal range (0.20-3.00)
• Mild anemia (Hb 11.1) is very common in pregnancy - WHO defines anemia in pregnancy as Hb < 11 g/dL (she is borderline)
• Epithelial cells (2-3/HPF) and leukocytes (2-3/HPF) in urine are within normal limits and commonly seen in pregnancy due to increased vaginal secretions and urinary tract changes
• Blood sugar 88 mg/dL - normal, rules out gestational diabetes at this level

2. Urinary Tract Infection (UTI) / Asymptomatic Bacteriuria

• Leukocytes 2-3/HPF with epithelial cells is at the borderline of significance
• No bacteria, no casts, no RBCs = sterile pyuria pattern
• In pregnant women, asymptomatic bacteriuria occurs in 2-7% and can present with low-grade pyuria before frank infection
• Important: In female urine, epithelial cells at this level may represent contamination from vaginal/vulvar secretions rather than true pathology
• Culture and sensitivity should be done to confirm or rule out

3. Vulvovaginal Contamination (Specimen Collection Artifact)

• 2-3 squamous epithelial cells/HPF is the classic finding when midstream urine collection is inadequate, especially in women
• No bacteria, no casts, clear urine, no albumin - all favor contamination rather than true infection
• Very common in young females; repeat midstream clean-catch recommended

SECONDARY - Consider If Symptomatic

4. Iron Deficiency Anemia

• Hb 11.1 g/dL in a 26-year-old female - most common cause is iron deficiency (menstrual loss, dietary)
• If pregnant: increased iron demand is the most common cause
• Next step: serum ferritin, TIBC, peripheral smear

5. Anemia of Pregnancy (Dilutional)

• Plasma volume expands 40-50% in pregnancy while RBC mass expands only 20-30%
• Results in physiological dilutional anemia - Hb commonly falls to 10.5-11.5 g/dL
• Hb 11.1 fits perfectly with this pattern

6. Subclinical Hypothyroidism / Hashimoto's Thyroiditis (LOW probability)

• TSH 2.07 is normal - this diagnosis is unlikely
• However, the fact that TSH was ordered suggests clinical suspicion (fatigue, weight gain, hair loss)
• If symptoms persist, re-check TSH with Free T4

7. Chronic Pelvic Inflammatory Disease (PID) / Cervicitis

• Can cause sterile pyuria with epithelial cells without overt bacteriuria
• Referred by a surgeon/gynecologist supports this workup
• Would need pelvic exam, cervical swab for Chlamydia/gonorrhea

LOWER PROBABILITY (Rule Out)

Recommended Next Steps

1. Urine C&S (culture and sensitivity) - to confirm/exclude bacterial UTI
2. Peripheral blood smear + serum ferritin - to characterize the anemia (iron deficiency vs. dilutional)
3. Repeat urine R/M with proper midstream clean-catch - if epithelial cells disappear, it was contamination
4. Confirm pregnancy status (if not already confirmed via clinical history)
5. Obstetric ultrasound - if pregnant, for dating and fetal assessment
6. If symptomatic for thyroid: Free T4

Bottom Line

• Physiological/iron deficiency anemia (Hb 11.1)
• Normal TSH
• Borderline pyuria + epithelial cells likely representing contamination OR early/asymptomatic UTI - urine culture is the key next step

⚠️ Note: This analysis is for educational/clinical support purposes. Final diagnosis must be made by the treating physician with full clinical history, examination findings, and symptom correlation.