In medicine, the BUN-to-creatinine ratio is the ratio of two serum laboratory values, the blood urea nitrogen (BUN) (mg/dL) and serum creatinine (Cr) (mg/dL). Outside the United States, particularly in Canada and Europe, the truncated term urea is used (though it is still the same blood chemical) and the units are different (mmol/L).
Your child must be both physically and emotionally ready for toilet training. Most children are ready to start when they are between 22 and 30 months of age, but every child is different. Toilet training usually becomes a long and frustrating process if you try to start it before your child is ready.
Most parents are familiar with the traditional advice that their child will likely be ready for potty training when they are some time between 18 months to 3 years old. They may be surprised by the idea that you could try to potty train your baby when he is just 2, 3, or 4 months old.