Amorphous urates: What they are, diagnosis and treatment

 

Amorphous urates are a type of crystal that varies in colour from yellow to black, identified in the urine test. This can arise due to the cooling of the sample during packaging for transport or due to the acidic pH of the urine, with the values ​​being observed equal to or less than 5.5.

Examination of abnormal urine elements and sediment (EAS) can be performed manually or automatically. Automated urinalysis devices available on the market are accurate, reproducible, faster and much less labor intensive (walk-away instruments) than standard manual microscopy. It can be run directly at patient-side without any further sample manipulation (e.g. refrigeration, centrifugation etc.). It has the potential to markedly reduce human factor from interpretation by consistently applying the same algorithm to the analysis of every sample.

The Erba Laura XL is an automated device that performs three phases that make up the EAS, from the physical and chemical part to the sedimentoscopy/microscopy, serving different audiences that also include pediatric and geriatric samples.

Image 1: Image of amorphous urates present in the sediment identified by the automation system of Erba Laura XL

During the transport of urine, many laboratories cool the samples for transport to the laboratory headquarters, where the sample processing will actually be carried out. However, we must not forget that these samples have a processing time of up to 2 hours, as the low temperature favors the crystallization of some urine components, with the formation of amorphous urates. Its appearance does not cause symptoms, being observed only in the type 1 urine test or the EAS, also called abnormal elements of the sediment.

When there is a large amount of urates in the urine, it is possible to visualize the macroscopic alteration, as it changes colour from yellow to pink.

The appearance of this crystal in the urine can mean several situations, such as:

·         Drop

·         Chronic inflammation of the kidneys

·         high protein diet

·         low water intake

·         gallstone

·         kidney stone

·         liver disease

·         Kidney disease

·         Calcium-rich diet

·         Diet rich in vitamin C.

The treatment for amorphous urates is carried out according to the cause of its appearance, and the doctor may indicate a change in eating habits, in order to avoid the ingestion of foods rich in calcium or proteins. This is in addition to other clinical procedures that may be considered, caused by the impairment of some organ. It is worth noting that clinical conduct must be guided by a physician so that the patient has a more assertive treatment.

Author: Juliana Oliveira/ Scientific Advisor / Master in Pathology-UFF

Bibliographic reference:

HOLMES, JH and other- Urinalysis and Renal Function- Preworkshop Manual.1st ed.1962. American Society of Clinical Pathologists. Chicago. Illinois.

HALLMANN, L. Clinical and Microscopic Analysis. 1st ed. 1975. Scientific EditorialMedical. Barcelona.

LOPATA, Victor José et al. Analysis of clinical and laboratory data associated with urolithiasis in patients from a clinical analysis laboratory . Academic Vision. Vol 17. 3rd ed; 18-28, 2016.