A four year old female intact guinea pig (Cavia porcello) presented for a diagnostic recheck on a previously diagnosed protein losing nephropathy (PLN). The patient had significant ventral pitting edema and cachexia on physical exam. Blood was collected but clotted on multiple occasions. On the third attempt, the patient arrested. Basic life support was initiated and continued for approximately 6.5 minutes, unsuccessfully. The patient’s body was submitted for a necropsy and the blood was submitted for analysis. Diagnostic result trends supported worsening renal pathology and nephrotic syndrome. Gross necropsy reported presumptive exsanguination and chronic, severe and diffuse nephropathy; the final pathologic diagnosis was chronic progressive nephropathy. This case report will discuss the case of PLN and nephrotic syndrome (NS) in a guinea pig. Defined as hypoalbuminemia, hyperlipidemia, proteinuria and fluid accumulation in interstitial spaces and/or body cavities, NS can lead to a hypercoagulable state, which combined with the stress of venipuncture and concurrent comorbidities, contributed to cardiac arrest.