CALCIUM AND PHOSPHATE

Question 1

Ca and PO4
Reagent

Answer 1

1000 uL or 1 mL in all tubes

Question 2

Ca and PO4
Serum
Water
Standard

Answer 2

10 uL

Question 3

Ca Mix and incubate

Answer 3

37C for 2 minutes

Question 4

PO4 Mix and incubate

Answer 4

37C for 5 minutes

Question 5

Ca Absorbance

Answer 5

660 nm

Question 6

PO4 Absorbance

Answer 6

340 nm

Question 7

Ca CALCULATION

Answer 7

8.6 - 10.3 mg/dL

Question 8

PO4 CALCULATION

Answer 8

5

Question 9

Ca EXPECTED VALUES

Answer 9

8.6 – 10.3 mg/dL(2.15 – 2.57 mmol/L)

Question 10

PO4 EXPECTED VALUES

Answer 10

Adult 2.5 – 4.5 mg/dL (0.81 – 1.45 mmol/L)
Children 4.0 – 7.0 mg/dL (1.29 – 2.26 mmol/L)

Question 11

Ca Method

Answer 11

Dye-binding Method (Arsenazo III dye)

Question 12

PO4 Method

Answer 12

Fiske and Subbarow Method

Question 13

Phosphate

The [?] react with [?] to form a [?].

Answer 13

phosphate ions

ammonium molybdate

phosphomolybdate complex

Question 14

Phosphate

The colorless phosphomolybdate complex can be measured [?] by [?] at [?].

Answer 14

directly

ultraviolet (UV) absorption

340 nm

Question 15

Phosphate

An [?] pH is necessary for the formation of complexes.

Answer 15

acid

Question 16

[?] combines with calcium at [?] to form a [?], the absorbance of which is measured at [?].

Answer 16

Arsenazo III

slight acidic pH

blue complex

660 nm

Question 17

Calcium

The reaction has [?] and interference from [?] is avoided due to pH.

Answer 17

high specificity

magnesium

Question 18

Ca Reagent Composition:

Answer 18

Arsenazo III (purple)
Good’s buffer (pH 6.8)
Stabilizers

Question 19

PO4 Reagent Composition:

Answer 19

Ammonium molybdate
Sulfuric acid
Surfactant

Question 20

Total calcium is stable for [?] and for [?].

Answer 20

7 days at 2 - 8C

several months when frozen at -20C

Question 21

Phosphate is considered to be stable in serum that has been separated from the clot for [?] and [?].

Answer 21

days at 4C

months when frozen

Question 22

Preferred sample Ca

Answer 22

Serum (preferred) heparinized plasma

Question 23

Ca Do not use

Answer 23

citrate, oxalate and EDTA as anticoagulant

Question 24

PO4 - is the preferred specimen.

Answer 24

Serum

Question 25

Although heparinized plasma is acceptable, levels of inorganic phosphate are about [?] lower than in serum.

Answer 25

0.2 – 0.3 mg/dL

Question 26

Phosphate

Anticoagulants such as [?] interfere with formation of the [?] and should not be used.

Answer 26

citrate, oxalate and EDTA

phosphomolybdate complex

Question 27

Phosphate

[?] may either decrease or increase with time, depending on the type of specimen, temperature, and duration of storage.

Answer 27

Inorganic phosphate in whole blood specimens

Question 28

Phosphate

Levels in plasma or serum are [?] with cells at room temperature or 37C.

Answer 28

increased by prolonged storage

Question 29

Phosphate

It is important to promptly separate serum or plasma from [?].

Answer 29

erythrocytes

Question 30

Phosphate

Hemolyzed specimens are unacceptable because erythrocytes contain high concentrations of [?] which can be hydrolyzed to [?] during storage.

Answer 30

organic phosphate esters

inorganic phosphate

Question 31

Phosphate

Inorganic phosphate increases by [?] in hemolyzed specimens stored at 4C.

Answer 31

4 – 5 mg/dL per day

Question 32

Phosphate

[?] may also be hydrolyzed by assay conditions, resulting in over-estimation of inorganic phosphate levels.

Answer 32

Glucose phosphate, creatine phosphate and other organic phosphates