Urinalysis: A useful test for risk stratification of COVID-19
Clinicians have been relying on urine testing, which is giving medical experts a plethora of information, to monitor patients’ renal function which can be impacted by COVID-19.
Involvement of kidney
Researchers have been able to successfully isolate SARS-CoV-2 from the urine sample of an infected patient, suggesting that the virus attacks the kidneys. SARS-CoV-2 uses the Angiotensin-converting enzyme (ACE 2) receptor for entry and multiplication. Therefore cells expressing ACE2 may be target cells and are thus susceptible to SARS-CoV-2 infection. Such cells include alveolar type II cells of the lungs and podocytes which are typically found in the kidneys. Once it enters the cells, the virus causes sepsis leading to cytokine storm syndrome or direct cellular injury.
Acute Kidney Injury (AKI) - an independent risk factor
Acute Kidney Injury (AKI) or acute renal failure is a sudden episode of kidney failure or damage that happens within in a short period of time. It is most common in people who are already hospitalized, particularly critically ill patients. Initial studies have indicated that COVID-19 causes complications such as Rhabdomyolysis (serious syndrome due to direct or indirect muscle injury) leading to renal failure. In fact, one study also showed that 34% patients developed albuminuria (presence of increased albumin in blood) on the first day of admission, 63% developed proteinuria (presence of protein in blood) during their hospital stay*.
Proteins are usually found in the blood and normally do not pass into the urine. However, if the glomeruli or tubules in the kidneys are damaged, proteins will flow into urine.
Also, blood urea nitrogen was elevated in two-thirds of the patients who died. On further investigation, CT scan of the kidney confirmed inflammation of the kidney tissues, due to the infection.
AKI was thus identified as an independent risk factor among patients with COVID-19 and is associated with higher mortality than in patients without AKI. Not to forget, the elderly patients and cases with co-morbidities such as hypertension and heart failure.
A simple, non-invasive test
Urinalysis (or in other words urine testing) is one of the most important non-invasive test which gives an early indication of the extent of AKI due to COVID-19. Since urinalysis detects early renal impairment it is been considered more effective than blood tests to predict the disease severity in COVID-19 patients.
Urinalysis consists of urine chemistry and microscopy that can provide novel insights in the patho-physiology of COVID-19 and biomarkers of disease severity. Urine chemistry is a readily available, rapid and inexpensive test that aids in identifying presence of proteins, RBC and leucocyte esterase. On the other hand, urine microscopy or sediment analysis is a valuable tool for confirming the diagnosis of AKI especially amongst hospitalized COVID-19 patients.
Can a urine test diagnose COVID-19?
As mentioned above, COVID-19 can cause damage to the kidney, the effect of which can be analyzed in the urine. Urine of an infected person can also give an indication of disease severity.
Studies** have indicated that COVID-19 is rarely detected in urine and hence urinalysis can’t be used for diagnosis of the infection. However, infection transmission through urine still remains possible. Transmission is more likely in adult patients in moderate and severe disease. Therefore, caution should be exerted when dealing with COVID-19 infected patients during medical interventions like endoscopy and urethral catheterization.
Transasia’s urine portfolio
Transasia Bio-Medicals offers a wide portfolio of URINALYSIS solutions from small to high volume workloads.
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