Modern Pediatrics. Ukraine. (2025).8(152): 6-12. doi: 10.15574/SP.2025.8(152).612
Petritsa N. A.¹, Luk’yanenko N. S.^1,2, Kech N. R.^1,2
1SI "Institute of Hereditary Pathology of the NAMS of Ukraine", Lviv, Ukraine
²Danylo Halytsky Lviv National Medical University, Ukraine

For citation: Petritsa NA, Luk’yanenko NS, Kech NR. (2025). Diagnostic markers of kidney damage in children with post-COVID-19 syndrome. Modern Pediatrics. Ukraine. 8(152): 6-12. doi: 10.15574/SP.2025.8(152).612.
Article received: Jun 12, 2025. Accepted for publication: Dec 15, 2025.

The SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2) has been showin to adversely affect kidney tissue, causing inflammatory, autoimmune, and metabolic disorders, which pose a risk of developing acute and chronic nephropathies. The lack of clear diagnostic criteria for kidney damage in children with post-COVID-19 syndrome (condition after recovering from COVID-19) complicates timely treatment and prevention of complications. Identifying early diagnostic markers of kidney damage is important for early detection of pathology, which would improve medical surveillance and timely treatment.
Aim – to identify early diagnostic markers of kidney injury in children with post-COVID-19 syndrome.
Materials and methods. This observational study included 30 children under the age of 18 diagnosed with post-COVID-19 syndrome who had documented urinary abnormalities during the acute phase of SARS-CoV-2 infection and were hospitalized between January 2023 and July 2024. The source of information was the "Medical Record of an Inpatient". The study was conducted using a targeted selective screening method. All children underwent comprehensive clinical and laboratory examinations according to generally accepted pediatric standards. The following indicators of kidney functional status were assessed: anti-crystallization capacity of urine (ACCU), daily salt excretion, lipid peroxidation (LPO) products, polar lipids (PL), and a series of urinalysis tests. The study results were compared with data from 40 children in the control group. Statistical analysis was performed using the EZR package (R-statistics).
Results. It was found that the intensity of tissue hypoxia and dysfunction of the proximal nephron segments directly correlates with SARS-CoV-2-induced damage. This is evidenced by a decrease in ACCU towards calcium phosphates, reduced phosphate excretion, increased excretion of LPO products and appearance of PL, as well as a higher frequency of proteinuria and calciuria in urine compared to the control group.
Conclusions. The possibility of predicting and diagnosing post-COVID-19 syndrome in children with urinary tract damage using non-invasive biochemical markers of tissue hypoxia and renal parenchymal membranolysis in children's daily urine has been confirmed.
The study was conducted in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of all institutions mentioned in the study. Informed consent was obtained from the parents and children.
The authors declare no conflict of interest.
Keywords: children, kidney functional status, post-COVID-19 syndrome.

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