Acute Kidney Injury in Dogs and Cats: Biomarkers vs Functional Markers

The VetEmCrit Academy built for ER and ICU vets who want to grow, level up, and learn together: https://academy.vetemcrit.com/join Learn to read any ECG with confidence — https://academy.vetemcrit.com/ecg-mas... Free RACE-Approved Training on Intravenous Potassium Supplementation: https://academy.vetemcrit.com/iv-pota... Free Acid-Base Analysis Workshop: https://academy.vetemcrit.com/free-wo... Free veterinary emergency tools, protocols, and articles: https://vetemcrit.com/ If you're new to my channel, I am Igor Yankin, a small animal emergency and critical care specialist based in Texas. You might know me as the founder of vetemcrit.com, where I’ve spent the last several years creating evidence-based tools, case discussions, and training for veterinarians working on the front lines of emergency and critical care. My story in ECC started back in 2010 when I worked full-time ER shifts. After five intense years, I completed a small animal rotating internship at Oregon State University, followed by an ECC residency at the University of Florida. Since 2019, I’ve been practicing as a veterinary criticalist. Over the years, I’ve noticed that what most ER vets and techs need isn’t just more information, it’s a way to connect, discuss real cases, and keep growing together without judgment. That realization inspired me to create something new, a space where emergency and critical care professionals can come together, learn, and support each other in a meaningful way. That space is now called the VetEmCrit Academy — a growing community for those who want to stay sharp, confident, and connected in ECC practice. If you’re ready to see what’s inside and how it works, learn more by going to https://academy.vetemcrit.com/join AKI Diagnosis: Functional Markers vs Biomarkers (Creatinine, GFR, NGAL) This episode explains the difference between functional markers and biomarkers for diagnosing acute kidney injury (AKI). Functional markers estimate kidney function, including direct but cumbersome GFR measurement, biochemical surrogates of GFR such as creatinine, BUN, and SDMA, and urine output, each with limitations. Biomarkers indicate structural kidney tissue damage even when function may still appear preserved; commercially available examples include NGAL, KIM-1, urine GGT, urine alkaline phosphatase, urine cystatin B, and serum amyloid A. Using a timeline example after anesthesia/surgery, the script shows creatinine as a delayed AKI marker that may not cross threshold until ~48 hours, whereas NGAL can rise within minutes to hours and peak at 3–6 hours. It also reviews the exponential creatinine–GFR relationship, emphasizing that small creatinine increases can reflect large GFR drops in normal patients but smaller GFR changes in established CKD. 00:00 Functional vs Biomarkers 00:42 Common Functional Markers 01:31 What Biomarkers Detect 02:38 Creatinine vs NGAL Timeline 03:26 Why Creatinine Lags 05:43 Creatinine and GFR Curve 06:20 Small Creatinine Big GFR Drop 07:45 CKD Changes Interpretation 08:45 Key Clinical Takeaways