Quiz 3: Phosphorus

Question 1

Locations of Phosphorus in the body

Answer 1

• 80% of phosphate found in bone
• 20% in soft tissue
• < 1 % in serum/plasma

Question 2

Causes of interference in Phosphorus measurement

Answer 2

EDTA, Citrate, oxalate anticoagulants interfere with most assay methods.
Hemolysis increases PO4 since it is predominately intracellular

Question 3

Phosphorus Reference Values

Answer 3

Serum/Plasma: 2.7 - 4.5 mg/dL

Urine: 0.4 -1.3 g/d (400-1300 mg/d)

Question 4

Measurement of Inorganic Phosphorus

Answer 4

Only form measured by Lab
Phosphate ion + ammonium molybdate = phosphomolybdate complex
When a stannous Cl reducer is added = molybdate blue complex forms, which can be read at 600 - 700 nm.

Question 5

Hyperphosphatemia

Answer 5

Chronic Renal Failure
Hypoparathyroidism
Excess Vitamin D

Question 6

Hypophosphatemia

Answer 6

–not common
Hyperparathyroidism
Impaired Renal Absorption

Question 7

Phosphorus

Answer 7

Has an inverse relationship with Ca

Question 8

Phosphorus Regulation

Answer 8

Absorption and excretion in Kidneys, caused by PTH (excretion), and VitD (intestinal and renal reabsorption)