How to Detect AKI?

Detecting AKI: Blood Tests, Urine Output & Imaging Explained

AKI is diagnosed using KDIGO criteria, which include changes in serum creatinine and/or urine output, interpreted in the clinical context, recognizing that creatinine may lag behind actual kidney injury. A significant rise in the creatinine level in the blood indicates that the kidneys are not functioning properly. Doctors may also consider other factors, such as the overall clinical picture and urine output, to determine the severity of AKI.

Diagnostic Tests to Detect AKI

Here are some of those diagnostic tests which can detect and determine AKI in patients:

Blood Tests

Common blood tests that are done to detect AKI are as follows:

1. Serum Creatinine: It measures the creatinine level in the blood, a common waste product that your kidneys filter frequently. Elevated levels of creatinine in your blood can indicate underlying kidney-related issues.
2. Blood Urea Nitrogen (BUN): BUN measures blood urea levels and is less specific than creatinine, as it can be influenced by dehydration, GI bleeding, and protein intake. These two elements are also waste products filtered by your kidneys. Higher levels of urea or nitrogen in your blood may indicate reduced kidney function.
3. Estimated Glomerular Filtration Rate (EGFR): The following test calculates and determines the total filtration rate based on serum creatinine levels, age, and sex. eGFR is not reliable in AKI and should be interpreted cautiously; serial creatinine trends and urine output are preferred.   
4. Electrolytes: It checks the levels of potassium, sodium, and bicarbonate to detect imbalances. Abnormal levels of electrolytes in your body indicate kidney problems and require immediate medical attention. 
    

Urine Output

Healthcare providers monitor urine production regularly to track kidney function. A decrease in the levels of urine output can be a sign of AKI. This test is essential for patients who are suffering from serious kidney-related problems for a prolonged period.  

Urinalysis

It is a general urine test that identifies potential causes, such as urinary tract infections. This test measures and calculates the albumin-creatinine ratio (ACR), which is the ratio of albumin levels and creatinine levels. ACR is primarily used for CKD detection and prognosis, not for diagnosing AKI, though proteinuria may provide etiologic clues.

Ultrasound

Renal ultrasound in AKI is mainly used to exclude obstruction; kidney size is often normal. Additionally, it also assesses the thickness of the renal parenchyma (cortex and medulla), which can be thinned in case of acute kidney diseases.

Kidney Biopsy

Kidney biopsy is rarely performed in AKI and is reserved for suspected intrinsic renal diseases (e.g., glomerulonephritis, vasculitis) when diagnosis is unclear. It detects the cause and effect of injuries in your kidney tissues. Doctors usually recommend this test if they fail to detect the cause of AKI from apparent blood tests.

Furosemide Stress Testing

In this diagnostic test, doctors infuse furosemide (a diuretic) into the patient's body and monitor urine output. A low output signifies a poor response to furosemide and may suggest a higher risk of AKI development. FST is used to predict AKI progression and the likelihood of needing RRT, not to prevent it.

Fractional Excretion of Sodium (FENa) and Urea (FEUrea)

The following urine test measures the percentage of filtered sodium excreted. Additionally, it provides insight into how well the kidneys reabsorb sodium. Apart from this, it primarily focuses on differentiating between intrinsic and prerenal kidney causes of acute kidney injury (AKI).

Early diagnosis and treatment are crucial to prevent complications and improve outcomes. Understanding the cause of AKI is important for appropriate treatment. AKI can range from mild to severe, depending on the assessment of the creatinine levels and urine outputs.

Disclaimer: This article is intended for informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment. Acute kidney injury (AKI) is a complex medical condition that requires evaluation by a qualified healthcare professional. The information provided here is based on general clinical guidelines and may not apply to all individuals or clinical situations. Diagnostic tests and interpretations should always be considered in the context of a patient’s overall health, medical history, and clinical findings. Readers should not rely on this content as a substitute for professional medical consultation and should seek advice from a licensed healthcare provider for any concerns related to kidney health or symptoms suggestive of acute kidney injury.

Also Read:

→ Pap Smear Results Explained Simply

→ Pap Smear Risks - What You Need to Know

→ Signs of Midlife Depression in Men and How to Cope

→ Step-by-Step Guide to Your Pap Smear Test

→ Why are Kids so Attached to Their Mothers