Urinalysis and Body Fluids CRg Unit 2; Session 5 Crystals Found in the Urine Microscopic Examination - Part C, Common Alkaline Crystals

Alkaline urine pH ≥ 7.0, however, crystals don’t always follow the rules regarding pH Phosphates Amorphous phosphates Triple phosphates Calcium phosphates Calcium Carbonate Ammonium biurate Normal Crystals in Alkaline Urine Obj. Explain why performing all aspects of the urinalysis as soon as possible will provide the most accurate assessment of macroscopic and microscopic characteristics. Obj. Identify or describe the normal and abnormal constituents that may be seen in the urine microscopic including…….cells… acid, alkaline and pathologically significant crystals….

Amorphous Phosphates May appear similar to amorphous urates Differentiate: Heavy white precipitate after refrigeration Alkaline ph Soluble in acetic acid

Triple Phosphate Triple (ammonium magnesium) phosphate Also called struvite Appearance Distinct shape Colorless, prism, or coffin-lid shaped Will Polarize No clinical significance, though makes up 10-20% of urinary calculi Exhibit distinct prism shape often termed “coffin-lid”. Some views may resemble picture frames, or the roof line of a house as seen from an airplane.

Triple Phosphate Triple phosphate crystals (can look like fern leaf when going into solution) Polarizes light Demonstrates birefringence Dissolves in –Acetic acid

Calcium phosphate Small, flat plates; rectangle or wedged shaped May be single, or rosettes No clinical significance

Calcium Carbonate Ca Carbonate Small, colorless dumbbell, and spherical shapes Appear similar to dumbbell shaped calcium oxalate Gas produced with addition of acetic acid No clinical significance

Ammonium Biurate Rarely seen in freshly voided urine Abnormal only if found in freshly voided urine Common in old specimens and with urea-splitting bacteria Only urates in alkaline urine Low power magnification

Ammonium Biurate Yellow–brown spherical bodies with long, irregular spicules Termed “thorn apple” or “cocklebur’, “Medusa head” Rare form has no spicules Dissolves in Acetic acid NaOH And when heated (60 o C

 Lillian Mundt & Kristy Shanahan, Graff’s Textbook of Urinalysis and Body Fluids, 2 nd Ed.  Susan Strassinger & Marjorie Di Lorenzo, Urinalysis and Body Fluids, 5 th Ed.  Meryl Haber, MD, A Primer of Microscopic Urinalysis, 2 nd Ed.  Nikon Microscopy, The Source for Microscopy Education. Website References