Vitamin B-12 is an essential vitamin. Low blood levels of B12 can cause: Anemia and pernicious anemia, loss of balance , numbness or tingling in the arms and legs, and weakness

Cortisol (hydrocortisone) is the most prominent glucocorticosteroid, and it is essential for the maintenance of several body functions. The most important physiological effects of cortisol are that it raises blood sugar levels (enhances gluconeogenesis, or breaks down glucose) and lowers inflammation and the immune system.

The GGT bood test looks for an enzyme, or protein, called gamma-glutamyl transpeptidase (GGT) in your blood. GGT is found in liver cells. This test helps your doctor look for possible damage to your liver or its ducts. It can also help tell the difference between liver and bone disease if your results from a different blood test called alkaline phosphatase are abnormal. Higher than normal test results could be a sign of liver damage from diseases such as hepatitis, cirrhosis, tumors, or pancreatic cancer. But a higher than normal GGT level does not tell you the specific cause of liver disease or damage.

B12 and folic acid blood testing help doctors diagnose central nervous system disorders, anemia, and malabsorption syndromes. B12 and folic acid also play an important role in energy level, muscle strength and memory. Because B12 and folate are derived solely from dietary intake, such as egg yolks, beef, poultry and fish, many people are deficient in these important vitamins.

Insulin-like Growth Factor 1, also known as IGF-1, is used as a biomarker for blood levels of human growth hormone. It is a hormone produced by the liver and other tissues which affects growth-promoting activities and glucose metabolism. The blood level of IGF-1 appears to fluctuate over 24 hours and is found to be related to growth hormone secretion.

The serum iron test measures the amount of iron in your blood. The total iron-binding capacity (TIBC) test looks at how well the iron moves through your body.