Kidney function assessment

Blood urea nitrogen (BUN) and creatinine levels falling outside the normal range (bearing in mind that both their reference values can vary between different species) are clear hints of kidney disfunction.

Other parameters measured to assess renal function are: the (lowered) glomerular filtration rate (GFR), Phosphate (PO4), Potassium (K), Protein (total), Sodium (Na), Chloride and other analytes. Routine haematology analysis is also recommended. IDEXX SDMA test is a useful tool to assess glomerular filtration rate (GFR) and detect changes to kidney function much earlier than with creatinine and BUN alone.

Symmetric Dimethyl Arginine (SDMA) is excreted from the kidneys; therefore, as kidney function or GFR decreases, SDMA increases. Studies have shown a very strong correlation between SDMA and GFR (R2 of 0.82 in cats; R2 of 0.85 in dogs). The benefit of using SDMA along with creatinine, which typically increases above the reference interval only after a 75% reduction in GFR, is that SDMA increases when there is on average a 40% decrease in GFR. In some cases, SDMA increases earlier when there is 25% reduction of GFR, representing 25% loss of kidney function. SDMA tests for dogs, cats, horses and rodents are currently available.

Neutrophil gelatinase-associated lipocalin (NGAL) is a promising diagnostic biomarker of early acute kidney injury (AKI) when measured in urine. Urine NGAL in AKI almost exclusively contains NGAL monomer from the kidney, whilst the plasma/serum pool contain different NGAL complexes from several sources and would therefore be expected to show poorer diagnostic performance in AKI

*In bold, IDEXX BioAnalytics tests and services available


*In bold, IDEXX BioAnalytics tests and services available