Includes liver and kidney function, glucose and electrolytes

The Rheumatoid Arthritis Factor is often evaluated in patients suspected of having any form of arthritis or destructive articular disease even though positive results can be due to other causes, and negative results do not rule out disease. But, in combination with signs and symptoms, it can play a role in both diagnosis and disease prognosis. It is part of the usual disease criteria of rheumatoid arthritis.

The thyroid stimulating hormone (TSH) is produced and secreted by the pituitary gland and stimulates the thyroid to produce T3 and T4. When TSH is elevated, low thyroid function may be indicated. If TSH is low it is indicative of high thyroid function. A study found that TSH was suppressed in all subjects after food, so fasting may be suggested although it is not reqired by Quest. Free T4 and Free T4 values did not change significantly after eating.

Phosphate (as Phosphorus) - Serum phosphorus (Phosphate) levels alone are of limited diagnostic value and should be correlated with serum calcium levels. An increased phosphorus with decreased calcium suggests either hypoparathyroidism or renal disease. A decreased phosphorus and an increased calcium suggests hyperparathyroidism or sarcoidosis. When both calcium and phosphorus are decreased diagnostic considerations include malabsorption, vitamin D deficiency and renal tubular acidosis. Increased phosphorus and normal or increased calcium suggests Milk-alkali syndrome or hypervitaminosis D.

Renin, also known as angiotensinogenase, is an enzyme that the kidneys produce to regulate aldosterone production. It’s also essential in the renin–angiotensin aldosterone system (RAAS) which maintains your body’s fluid balance and blood pressure. Aldosterone is the primary of several endogenous members of the class of mineralocorticoids in humans. Aldosterone tends to promote sodium and water retention, and lower plasma postasium concentrations.

A Magnesium RBC test can provide an earlier indicator of magnesium deficiency that a standard magnesium blood test. When levels are low, the body will pull magnesium from the cells to keep blood levels normal. In this case, a magnesium blood test may show normal levels while a magnesium RBC test will give a more accurate result.