II. Definitions
- Microscopic Hematuria
- Microscopic Hematuria: 3 or more RBCs/hpf
III. Technique
- Start with 10 ml of midstream urine
- Centrifuge for approximately 10 minutes (typically at near 2000 rpm)
- Discard supernatant
- Suspend sediment in 0.3 ml saline or supernatant
- Examine under microscopy at 400x magnification
- Review at least 10-20 microscopic fields
IV. Interpretation: Inadequate sample (contaminated with vaginal contents)
- Squamous epithelial cells >5/hpf
V. Interpretation: Negative - Normal (<3 RBCs/hpf)
- Negative microscopy (<3 RBCs/hpf) and negative dipstick
- Normal
- Negative microscopy, but positive dipstick (False PositiveUrine Dipstick)
- See Urine Occult Blood for False Positive causes
- May suggest Myoglobinuria or Hemoglobinuria
- Rhabdomyolysis
- Intravascular Hemolysis with circulating free Hemoglobin
- Causes include Transfusion Reaction, DIC, Hemolytic Uremic Syndrome
- Precautions
- See Microscopic Hematuria for repeat Urinalysis timing
VI. Interpretation: Positive (3 or more RBCs per high powered field)
- Requires evaluation if present on repeat Urinalysis (at 3 weeks to 3 months)
- See Adult Microscopic Hematuria Causes
- See Hematuria in Adults
- See Hematuria in Children