NGAL: A Valuable Biomarker for Early Detection of Renal Damage

Nestled under the ribcage, the kidneys are primarily responsible for the filtration of toxins from the bloodstream and their elimination in urine. In instances of Acute Kidney Injury (AKI), however, this vital function is compromised.

AKI is the sudden loss of kidney function, which is commonly seen in hospitalised patients. Because patients don’t usually experience pain or distinct symptoms, AKI is difficult to identify. Early detection of AKI is paramount to prevent kidney damage from progressing into more enduring conditions such as Chronic Kidney Disease (CKD). So, how can we detect AKI promptly? This is where Neutrophil Gelatinase-Associated Lipocalin (NAGL), a promising biomarker for the early detection of renal injury, comes into focus.

Until recently, assessing the risk of AKI has relied on measuring changes in serum creatinine (sCr) and urine output.  Creatinine is a waste product formed by the muscles. Normally, the kidney filters creatinine and other waste products out of the blood into the urine. Therefore, high serum creatinine levels indicate disruption to kidney function, suggesting AKI. However, a limitation of the sCr test is that it is affected by extrarenal factors such as muscle mass; people with higher muscle mass have higher serum creatinine. Additionally, an increase in this biomarker becomes evident once the renal function is irreversibly damaged.

NGAL’s ability to rapidly detect kidney damage hours to days before sCr, renders it a more fitting biomarker to prevent total kidney dysfunction. 

Among currently proposed biomarkers for AKI, the most notable is NGAL. NGAL is a small protein rapidly induced from the kidney tubule upon insult. It is detected in the bloodstream within hours of renal damage. NGAL levels swiftly rise much before the appearance of other renal markers. Such characteristics render NGAL a promising biomarker in quickly pinpointing kidney damage.

The concentration of NGAL present in a patient's urine is determined using a particle-enhanced laboratory technique. This involves quantifying the particles in the solution by measuring the reduced transmitted light intensity through the urine sample.

In conclusion, the early detection of AKI remains a critical challenge, but NGAL emerges as a promising biomarker for promptly detecting renal injury before total loss of kidney function unfolds. NGAL offers a significant advantage over traditional biomarkers like serum creatinine- its swift induction upon kidney injury allows clinicians and healthcare providers to intervene before renal dysfunction manifests.

Written by Fozia Hassan

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