Calcium/PTH lab

Question 1

what is the coefficient of variation (CV%)?

Answer 1

The imprecision of error of analysis

Question 2

How would you calculate the coefficient of variation (CV%)?

Answer 2

Cv% = SD x 100 divided by Mean Result

Question 3

If there is a Gaussian distribution of results (bell shaped curve), what percentage of the population will fall into the reference range? What percentage of healthy people will have a results higher or lower than the reference range?

Answer 3

95%

2.5%

Question 4

what are 3 common causes of hypocalcaemia?

Answer 4

hypoparathyroidism
magnesium deficiency
Vitamin D deficiency

Question 5

What causes hypoparathyroidism ?

Answer 5

autoimmune destruction of parathyroid glands

surgical removal of parathyroid glands

Question 6

What causes vitamin D deficiency ?

Answer 6

Malabsorption/low dietary intake/lack of sun
Defective 25-alpha hydroxylation (liver cirrhosis)
Defective 1-alpha hydroxylation (renal failure)
genetic syndrome e.g. rickets

Question 7

what effect does low Mg have on PTH levels?

Answer 7

Low Mg = reduced PTH secretion

Question 8

what are the 3 common causes of hypercalcaemia?

Answer 8

malignant disease
Hyperparathyroidism
Miscellaneous

Question 9

what are miscellaneous reasons for hypercalcaemia?

Answer 9

Drugs (thiazide diuretics, lithium)

chronic granulomatous disease