Abnormal Urine Crystals
Abnormal urine crystals may be the result of medical examination or treatment (iatrogenic origin) or may be
associated with a metabolic disorder. The table below lists abnormal crystals that may be observed during a
microscopic urine sediment examination.
Crystal
Ampicillin
Origin
Iatrogenic
Calcium
oxalate
Iatrogenic
Image





dihydrate
Description
Colorless
Clusters of long
needles
Significance
High levels of
antibiotic
Colorless
Envelope (dihydrate
form)
Oval, dumbbell
(monohydrate form)
Ethylene glycol
ingestion
Note that calcium oxalate
crystals can be found in
both normal and abnormal
urine, and that they can be
found in a range of urine
pH from acidic to neutral.
monohydrate
Radiographic
contrast
media
Iatrogenic



Colorless
Flat elongated
plates; sometimes
with corner notches
Can resemble
cholesterol crystals
Increased urine
specific gravity
due to
intravenous
administration of
radiographic
contrast media
Page 1 of 3, revised January 1, 2017
Abnormal Urine Crystals
Crystal
Sulfanimide
Origin
Iatrogenic
Bilirubin
Metabolic
Disorders
Image




Description
Yellow-brown
Often forms
fan-shaped
structures, but
shapes vary
with drug type
Significance
Drug-associated
Bright yellow to
yellow-brown
Fine
amorphous
needles
Liver disease
Cholesterol
Metabolic
Disorders


Colorless
Flat plates with
corner notches
Lipiduria, proteinuria
Cystine
Metabolic
Disorders


Colorless
Six-sided
plates
Refractile
Cystinosis or cystinuria
In cystinuria, the renal
tubules do not have the
ability to reabsorb
cystine crystals. Without
reabsorption, cystine
crystals are eliminated in
the urine. The solubility of
cystine crystals is low,
resulting in the formation
of renal calculi (kidney
stones).
Prolonged
hemoglobinuria or
myoglobinuria
Appearance in urine 2-3
days post hemolytic
event

Hemosiderin
Metabolic
Disorders


Brown
Granules in
clumps
Page 2 of 3, revised January 1, 2017
Abnormal Urine Crystals
Crystal
Leucine
Origin
Metabolic
Disorders
Tyrosine
Metabolic
Disorders
Image




Description
Dark yellow/brown
Spheres with radial
striations and
concentric circles
Significance
Liver disease,
aminoaciduria
Colorless to brown
Fine needles
Liver disease,
aminoaciduria
Page 3 of 3, revised January 1, 2017