Yups, Low BUN means that your kidney functions are at the lowest and thing cannot be good, if it is continued for long...... :(
Hi, “blood urea nitrogen (BUN) measures the amount of urea nitrogen, a waste product of protein metabolism, in the blood. Urea is formed by the liver and carried by the blood to the kidneys for excretion. Because urea is cleared from the bloodstream by the kidneys, a test measuring how much urea nitrogen remains in the blood can be used as a test of renal function. However, there are many factors besides renal disease that can cause BUN alterations, including protein breakdown, hydration status, and liver failure.
A decreased BUN may be seen in:
• Liver failure
• Malnutrition
• Anabolic steroid use
• Overhydration, Which can result from prolonged intravenous fluids
• Pregnancy (due to increased plasma volume)
• Impaired nutrient absorption
• Syndrome of inappropriate anti-diuretic secretion (SIADH) “
Taken from website http://www.rnceus.com/renal/renalbun.html
But, in your case, relax; it does not seem to worrisome as your other parameters are more or less ok.
I forgot to mention the SED - RATE 21 HIGH 0 - 20