Basic Concepts in Clinical Biochemistry-A Practical Guide.7z

13.6 Calculations

Plot a graph between amount of glucose at x-axis and absorbance at y-axis. Extrap-
olate glucose amount from the given sample from the graph. The glucose concentra-
tion in serum sample can also be calculated by using the following equation:

Plasma glucose¼

ODof testamount of standard mgðÞ 100

ODof standardvolume of sample mlðÞ

¼xmg=dl

13.7 Clinical Significance...............................

Normal range of blood glucose is 70–110 mg/dl. Increase in blood glucose in disease
conditions causes hyperglycemia, and decrease in blood glucose causes hypoglyce-
mia. Hyperglycemia is associated with diabetes mellitus and hyperactivity of thy-
roid, pituitary, and adrenal glands. A moderate hyperglycemia may also be found in
some intracranial disease such as meningitis, encephalitis, tumors, and hemorrhage.
Depending upon the type, degree, and duration of the anesthesia, quite a consider-
able rise in blood glucose may occur, sometimes to over 200 mg/dl, thus producing a
temporary glycosuria. The glucose concentration in fasting samples of 150–200 mg/
dl is very suggestive of diabetes mellitus, and over 200 mg/dl is almost diagnostic.
For fasting samples, a 6–8 h fast is required. Hyperglycemia is also observed in
pancreatitis and carcinoma of pancreas where increase in fasting blood sugar may
occur but except in advanced cases; levels are moderate and does not exceed 150 mg/
dl.
Hypoglycemia occurs most frequently as a result of overdosage with insulin in
the treatment of diabetes. Insulin secreting tumors of pancreas produce severe
hypoglycemia. The fasting blood glucose may be reduced in hypothyroidism (myx-
edema, cretinism) and hypoadrenalism (Addison’s disease), and starvation and
severe exercise may produce hypoglycemia. Increased glycogen storage in the
liver may cause hypoglycemia due to deficiency of an enzyme involved in the
breakdown of glycogen to glucose. Impaired absorption of glucose from intestine
in some type of steatorrhea also causes hypoglycemia, while alcohol ingestion also
causes hypoglycemia, due to increased oxidation of ethanol by forming more NADH
and reducing the available NAD+(Fig.13.1).

13.7 Clinical Significance 59