Urine normally contains many dissolved substances that are eliminated from the human body. These substances can form solid forms and even crystals if there is a change in the urine pH, the temperature of the urine or if the concentration of these dissolved substances increases in the urine.
There are different types of crystals that can be found in a urinalysis. These crystals are found in a urinalysis of a healthy person and not only in cases of different diseases. Crystals are usually identified by their nature, shape, color and size. Crystals of various natures like crystals of calcium oxalate, calcium phosphate, triple phosphate, uric acid, amorphous urates and amorphous phosphates are often found. In minor cases, however this can be associated with pathological conditions like urolithiasis, etc.
Amorphous crystals can be isolated or in clumps. They usually appear as aggregates of finely granular material varying in shape and size. These amorphous crystals can be phosphates, urates or xanthine in nature. Amorphous crystals are usually visualized at high magnification.
• Amorphous urates are yellow, yellow-brown or pinkish in color. They tend to form in acidic urine and their precipitate is pink with a cloudy appearance of the mixed urine. Amorphous urates are a normal presence in the urine.
• Amorphous phosphates are usually formed in alkaline urine and they are without a color. The precipitate of amorphous phosphates is white.
• Xanthine crystals are usually seen in cases when treatment with allopurinol is used for urate urolithiasis. They are usually in the form of amorphous crystals.
Various methods can be used to identify the presence of amorphous sediment in the urine. Dissolving the sediment in an alkaline or acidic solution will help determine the nature of the sediment. Another method for visualizing the amorphous sediments in the urine is heating the solution to 37 degrees C. Amorphous urates and amorphous phosphates have little clinical value.
Amorphous urates and amorphous phosphates are distinguished based on the urinary pH. Amorphous urates form a pink precipitation, while amorphous phosphates form a white precipitation.
Keep in mind that although crystals can indicate various diseases like the presence of kidney stones, crystals in the urine can continue to form even after micturition. This usually occurs due to changes in the temperature of the urine is stored at room temperature or in a refrigerator, changes of the urine pH due to the presence of microorganisms in the urine.