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.
The age at which children are toilet trained hasn't always been the same. In the 1940s, for example, most toddlers began potty training before they reached 18 months of age, according to a 2008 report in American Family Physician.. White parents also tend to begin training later than African American parents.