Blood travels throughout your body, and when too much glucose (sugar) is present, it disrupts the normal environment that the organ systems of your body function within. In turn, your body starts to exhibit signs that things are not working properly inside—those are the symptoms of diabetes people sometimes experience. If this problem—caused by a variety of factors—is left untreated, it can lead to a number of damaging complications such as heart attacks, strokes, blindness, kidney failure, and blood vessel disease that may require an amputation, nerve damage, and impotence in men.
The word mellitus (/məˈlaɪtəs/ or /ˈmɛlɪtəs/) comes from the classical Latin word mellītus, meaning "mellite"[114] (i.e. sweetened with honey;[114] honey-sweet[115]). The Latin word comes from mell-, which comes from mel, meaning "honey";[114][115] sweetness;[115] pleasant thing,[115] and the suffix -ītus,[114] whose meaning is the same as that of the English suffix "-ite".[116] It was Thomas Willis who in 1675 added "mellitus" to the word "diabetes" as a designation for the disease, when he noticed the urine of a diabetic had a sweet taste (glycosuria). This sweet taste had been noticed in urine by the ancient Greeks, Chinese, Egyptians, Indians, and Persians.
Clinistix and Diastix are paper strips or dipsticks that change color when dipped in urine. The test strip is compared to a chart that shows the amount of glucose in the urine based on the change in color. The level of glucose in the urine lags behind the level of glucose in the blood. Testing the urine with a test stick, paper strip, or tablet that changes color when sugar is present is not as accurate as blood testing, however it can give a fast and simple reading.
To diagnose diabetes, doctors will  take a medical history (ask you about symptoms) and ask for blood and urine samples. Finding protein and sugar in the urine are signs of type 2 diabetes. Increased glucose and triglyceride (a type of lipid or fat) levels in the blood are also common findings. In most cases, blood glucose levels are checked after a person has been fasting for 8 hours.
Fasting plasma glucose level: If your blood glucose level is 7.0 mmol/L or higher after having not eaten anything for at least 8 hours – called fasting – your doctor may diagnose diabetes. If your blood glucose level is between 6.1 to 6.9 mmol/L, your doctor may diagnose impaired fasting glucose or prediabetes (a condition that may later develop into diabetes).
The more common form of diabetes, Type II, occurs in approximately 3-5% of Americans under 50 years of age, and increases to 10-15% in those over 50. More than 90% of the diabetics in the United States are Type II diabetics. Sometimes called age-onset or adult-onset diabetes, this form of diabetes occurs most often in people who are overweight and who do not exercise. It is also more common in people of Native American, Hispanic, and African-American descent. People who have migrated to Western cultures from East India, Japan, and Australian Aboriginal cultures also are more likely to develop Type II diabetes than those who remain in their original countries.
The glucose level at which symptoms develop varies greatly from individual to individual (and from time to time in the same individual), depending in part on the duration of diabetes, the frequency of hypoglycemic episodes, the rate of fall of glycemia, and overall control. (Glucose is also the sole energy source for erythrocytes and the kidney medulla.)
A number of studies have looked for relationships between sugar and diabetes risk. A 2017 meta-analysis, based on nine reports of 15 cohort studies including 251,261 participants, found no significant effect of total sugars on the risk of developing type 2 diabetes.7 Those consuming the most sugar actually had a 9 percent lower risk of developing diabetes, compared with those consuming the least sugar, although the difference was not statistically significant (meaning that it could have been a chance result). Similarly, fructose was not significantly associated with diabetes risk. Sucrose appeared to have a significant protective association. Those consuming the most sucrose had 11 percent less risk of developing type 2 diabetes, compared with those consuming the least.
Type 2 diabetes was once rare in children and adolescents but has recently become more common. However, it usually begins in people older than 30 and becomes progressively more common with age. About 26% of people older than 65 have type 2 diabetes. People of certain racial and ethnic backgrounds are at increased risk of developing type 2 diabetes: blacks, Asian Americans, American Indians, and people of Spanish or Latin American ancestry who live in the United States have a twofold to threefold increased risk as compared with whites. Type 2 diabetes also tends to run in families.

Insulin Therapy. Exogenous insulin is given to patients with diabetes mellitus as a supplement to the insufficient amount of endogenous insulin that they produce. In some cases, this must make up for an absolute lack of insulin from the pancreas. Exogenous insulin is available in various types. It must be given by injection, usually subcutaneously, and because it is a potent drug, the dosage must be measured meticulously. Commonly, regular insulin, which is a fast-acting insulin with a short span of action, is mixed with one of the longer-acting insulins and both types are administered in one injection.

Type 2 diabetes, which is often diagnosed when a person has an A1C of at least 7 on two separate occasions, can lead to potentially serious issues, like neuropathy, or nerve damage; vision problems; an increased risk of heart disease; and other diabetes complications. A person’s A1C is the two- to three-month average of his or her blood sugar levels.