The found in two form which is the monohydrate

The urine includes
the component that needs to eliminate from the body as a waste such as
dissolved substances or solutes. The formation of crystals requires these
solutes and other factors like the increasing concentration of dissolved
substances and the increase of pH level in acid or alkaline. These factors
contributed to the condition of crystalluria which means the presence of
crystals in the urine. Crystals can be found in both healthy people and unhealthy

Type of crystal (Normal crystals)

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Uric Acid (Normal acid pH crystals)

One of the by-products of protein digestion is uric
acid. Uric acid crystals can be found in a variety of shapes and sizes. The
physical appearance under the microscope resembles rhomboids, parallelograms,
and barrel while the colour is between yellow to orange-brown.
Although it is normal when uric acid found in urine but
in the certain condition it is indicating some disease such as gout, uric
acid nephropathy, urate nephrolithiasis or kidney stone Sometimes, people who
receive chemotherapy drugs may also have uric acid crystals in their urine.

Calcium Oxalate (Normal acid pH crystals)



These crystals can be found in neutral or alkaline
urine but mostly in acidic urine. It appears as colourless crystals under the
microscope. It is found in two form which is the monohydrate form that is
dumbbell shape and dihydrate form which appear in an envelope shape. It can
be found in urine of normal individuals with intake of oxalate or vitamin c
in large amounts and also in patients with nephrolithiasis and acute renal

Hippuric (Normal acid pH crystals)

Hippuric acid crystals can be found in acid,
neutral, or slightly alkaline urine. These colourless crystals look like prisms
or needle-like in shape and usually will fuse together.

Amorphous Urate (Normal acid pH crystals)

It appears in pink for gross analysis but yellow
microscopically. These small crystals comprised of urates, xanthine or
phosphates and appear as dark or yellow-red granules in the urine sediment.

Amorphous Phosphate (Normal alkaline pH crystals)

This very small type of crystal is found in alkaline
urine with the colour of yellow to brownish colour but colourless under the microscope.
It has the shape of coffee-lid.

Calcium Phosphate (Normal alkaline pH crystals)

These colourless crystals having the shape like
bluntly ended needles, flat rectangles, rosettes or prisms.

Calcium Carbonate (Normal alkaline pH crystals)

Calcium carbonate crystals are colourless to yellow-brown
in colour which can result in brownish tinge. It may appear in dumbells or
spheres with radial striations or smaller crystals with a round to ovoid

Triple Phosphate or Struvite (Normal alkaline pH crystals)

It is composed of phosphate, magnesium and ammonium.
It appears in colourless, rectangular in shape or looks alike with the coffin
lid. People who associated with a bacterial urinary tract infection (UTI) caused
by urea-splitting bacteria and patients who have infected calculi (struvite
stones) more tend to have this crystal. The presence of
urease-positive bacteria able
to elevate the urine pH and free ammonia. Eventually, promote struvite
crystalluria (and urolithiasis).

Ammonium Biurate (Normal alkaline pH crystals)

Ammonium urate or biurate crystals generally found
in brown or yellow-brown spherical shape. Its appearance looks like “throny-apples” due to the irregular protrusions but
in some urine samples, it may resemble calcium carbonate due to its smooth

Amorphous Phosphate (Normal alkaline pH crystals)

Amorphous phosphates are found in alkaline urine.
These colourless granules usually appear in coffin-lid shape.


Type of crystals (Abnormal crystals)



The formation of bilirubin crystals is from
conjugated bilirubin that is water soluble. It has the appearance of needle-like
to granular shape and yellow in colour. It usually has to view under high
magnification due to its tiny size except when it aggregates into large
crystals. This type of crystal may be can found in the urine of hepatic
disorders associated patients.


This crystal present in the acidic urine of the patient
who associated with nephrotic syndrome. It looks like a colourless notched
rectangular plate.


Cystine crystals are colourless, look like hexagonal
shape or benzene rings. The present of cystine in acidic urine called as cystinuria.
This condition usually associated with an inherited disorder or amino acid
reabsorption defect in proximal tubular. The size of this crystals varies in
size from small to medium.


The acidic or neutral pH urine may have the presence
of this crystal. Leucine crystals usually found in the patient who has impaired
amino acid metabolism in the liver. The appearance of leucine crystals is
yellowish to the brownish sphere. It has the pattern of concentric circles
with striations.


These colourless or yellow cyrosine crystals appear
as fine needles in acidic or neutral urine. Tyrosine crystals may be seen in the
patient who has tyrosinemia and/or certain liver disorders which cause
impairment in amino acid metabolism.


Type of crystals (Drug-induced crystals)



These crystals can be found in striated shells
or “shocks of wheat” shape.



The figure A shows
the crystals in rectangular plates shape with needle crystals in the variety of
sizes while figure B shows a bundle of abundant, densely packed needles-like
crystals. The crystals can cause crystalline blockage and eventually lead to
an acute renal failure when the certain type of medications are given in high
doses or given to volume-depleted patients.


These crystals are
flat needles, bunches of small needles that often appear brownish. The
presence of sulphonamide crystals usually indicates administration of a certain
drug such as methamphetamine which is an illegal drug. However, their
presence sometimes also indicating kidney stone formation.



In conclusion, the
normal crystals can be classified into two type which is acidic and alkaline pH
crystals. Usually, these type of crystal is not indicating the pathologic
condition. However, abnormal crystals and drug-induced crystals are not
normally found in fresh urine which indicates pathologic condition.