SDMA: A sensitive biomarker

Symmetric Dimethylarginine (SDMA) has emerged as a sensitive biomarker, facilitating the early detection of kidney dysfunction. Its utility in identifying renal impairment in the preclinical stages underscores its significance in diagnostic algorithms. 

Values of creatinine above 1.6mg/dl or 140µmol/L should be closely monitored as they suggest CKD. If these values remain within the normal range, but other abnormalities are detected, such as an SDMA >18µg/dl (or persistently elevated SDMA > 14 µg/dl) or other consistent anomalies in successive examinations, such as low urine concentrations without an identifiable non-renal cause, renal-origin proteinuria (UPC > 0.4), abnormal renal palpation, or anomalous renal imaging, there are sufficient indications to estimate an early diagnosis of CKD (IRIS, 2023). 

Urine tests: Comprehensive renal evaluation

Analysing urine-specific gravity (USG) and proteinuria complements blood tests, providing a comprehensive evaluation of renal function. Subtle changes, like a decrease in normal urine concentration (USG < 1.035) or increases in UPC values (0.2-0.4 borderline proteinuric; > 0.4 proteinuric) (IRIS, 2023), can serve as early indicators, guiding diagnostic precision.

Imaging modalities: Beyond visualisation

Imaging modalities, including X-rays and ultrasounds, play a pivotal role in evaluating renal architecture. Detecting structural abnormalities and assessing parenchymal integrity inform therapeutic decisions and prognosis.

Renal biopsy: A window into histopathology

Renal biopsies, though invasive, offer unparalleled insights into histopathological changes. The specific information gleaned from biopsies is particularly valuable when considering advanced therapeutic options, such as kidney transplants. 

The purpose of renal biopsy is to gather valuable information for managing kidney disease more efficiently, often leading to a definitive diagnosis. This technique is increasingly utilised due to advancements in early detection of CKD, providing insights into the severity, activity, chronicity, and potential reversibility of pathological changes. This information forms the basis for clinical decisions regarding prognosis and treatment. 

To prevent complications, it is crucial to have stabilised the patient beforehand and possess a thorough understanding of the available biopsy techniques, using the necessary equipment and resources for its execution. Despite the simplest approach being a needle biopsy of the renal cortex under general anesthesia guided by ultrasound, it is imperative to tailor the technique to each patient (Bartges and Polzin, 2011).