Sediment Constituents (Normal Crystals) Flashcards
What is the excretion of crystals in urine called?
Crystalluria
What is the most recognizable but most insignificant part of urine sediment?
Crystals
What causes the formation of urine crystals?
Precipitation of urine solutes (salts, organic compounds, medication)
What is the most common association for the presence of crystals in fresh urine?
Concentrated specimen (high specific gravity)
What factors contribute to crystal formation?
pH, solute concentration, temperature
How are crystals usually reported?
Rare, few, moderate, or many per HPF
How are abnormal crystals quantified?
Averaged and reported per LPF
What are the normal acid crystals in urine?
Amorphous urates, uric acid, calcium oxalate (dihydrate and monohydrate), calcium sulfate, hippuric acid, acid urates, monosodium or sodium urates
What is the composition of amorphous urates?
Calcium, magnesium, sodium, potassium urates
What causes the fluffy orange or pink sediment of amorphous urates?
Uroerythrin
What is the appearance of amorphous urates under a microscope?
Yellow-brown
What do clumps of amorphous urates resemble?
Granular casts (pseudocasts)
What does amorphous urates turn into when acetic acid is added?
Uric acid
What does amorphous urates turn into when ammonium hydroxide is added?
Ammonium biurate
In what conditions is amorphous urate increased?
Gout and chemotherapy
What is amorphous urate soluble in?
Heat (60°C) and alkali
What type of crystal is pleomorphic and has many shapes?
Uric acid
What is uric acid a product of?
Purine metabolism
What shapes can uric acid crystals have?
Rhombic, 4-sided flat plate, lemon-shaped, wedges, football, barrel rosettes, irregular plates, laminated forms
What form of uric acid may be mistaken for cystine crystals?
Hexagonal form
At what pH is uric acid present?
<5.7
What form does uric acid take if the pH is >5.7?
Ionized form as urate
In what conditions is uric acid increased?
Lesch-Nyhan syndrome, chemotherapy, gout
What is uric acid soluble in?
Alkali
What is the most frequently observed urinary crystal?
Calcium oxalate
What is another name for dihydrate calcium oxalate?
Weddellite (double D letter - Di)
What shapes do weddellite calcium oxalate crystals have?
Envelope, bipyramidal/emerald-cut diamond