Phosphate (PO,); Phosphorus (P)

About 85% of the body's phosphorus is found in bones and teeth and is
combined with calcium. The rest of phosphorus is in the soft tissues . Phosphorus
in the blood exists as phosphate, which is necessary for the generation
of bony tissue; the metabolism of glucose, fats, and proteins; and the
storage and transfer of energy. The range of normal for adult phosphate
levels is significantly different than the range of normal for children. The
difference is partially attributed to the increased level of growth hormone
present in children until puberty.
Due to the relationship between calcium and phosphorus, blood phosphate
concentration is closely linked to plasma calcium. Increased phosphorus
levels are accompanied by a decrease in calcium and, conversely,
decreased phosphorus levels are accompanied by an increase in calcium.
Normal Range
Adults
2.7-4.5 mg/dl
Children
4.5-5.5 mg/dl
Blood Chemistry Tests (Part 1)
39
Variations from Normal. Hypopphosphatemia, increased phosphorus
level, is most commonly associated with kidney dysfunction as in renal insufficiency,
severe nephritis, and renal failure . Hypoparathyroidism, increased
growth hormone, vitamin D excess, bone tumors, and Addison's
disease also demonstrate increased phosphate concentrations . In most of
these situations, a decrease in plasma calcium is also present and diagnostically
significant .
Hypophosphatemia, decreased phosphorus level, is associated with
hyperparathyroidism, rickets in childhood, osteomalacia in adults, malabsorption
syndromes, malnutrition, and an excessive amount of insulin
in the body. Hypophosphatemia is accompanied by an increase in plasma
calcium.
Interfering Circumstances. A false increase in phosphate follows the use of
laxatives or enemas. Oral laxatives may increase phosphorus levels as much
as 5 mg/dL within a few hours. Destruction of red blood cells will also
cause hyperphosphatemia.

Bicarbonate (HCO,)

Bicarbonate plays an important role in the blood buffer system, which
helps maintain the normal blood pH of 7.4. Simply put, the blood buffer system
is activated by a buildup of positively charged hydrogen ions in the
body. When this buildup occurs, bicarbonate, a negatively charged ion,
combines with the hydrogen to produce a weak acid, or buffer, called carbonic
acid. After a series of chemical reactions, an equilibrium is established
and pH levels are held within the normal range. Variations in bicarbonate
concentrations will affect the pH levels in blood.
Bicarbonate also serves as a transport mechanism to move carbon dioxide
(CO2.) from the body tissues to the lungs where it is exhaled. Carbon
dioxide is a waste product and must be removed from the bloodstream .
Normal Range
22-26 mEq/L
Variations from Normal. Decreased bicarbonate concentrations results in
acidosis, a blood pH of 7.35 or less. Acidosis is seen in renal failure, a variety
of respiratory diseases in which the lungs retain carbon dioxide, and
poorly controlled diabetes mellitus.
Increased bicarbonate concentrations results in alkalosis, a blood pH
greater than 7.45 . Alkalosis is associated with hyperventilation, excess intake
or retention of bicarbonate, and loss of gastric acid due to vomiting or
potassium depletion.