LAB 5 - MAGNESIUM

Question 1

the normal human body contains about ____ of magnesium

Answer 1

20-80 g

Question 2

magnesium on our body is most stored in
what organs

Answer 2

bone and muscles

Question 3

what will happen to organs if there’s deficiency in Mg

Answer 3

can be subjected to immobilization

Question 4

magnesium is an essential component in many enzyme reactions either as a ___ or ____

Answer 4

metalloenzyme or an intermediary activator

Question 5

It is the most important in those reactions involving PT and PS

what do they stand for?

Answer 5

phosphate transfer and protein synthesis

Question 6

severe magnesium deficiency can result in impairment of __ function

Answer 6

neuromuscular

Question 7

Symptoms usually do not occur until magnesium levels fall below _____ mEq/L

Answer 7

1 mEq/L ( mmol/l)

Question 8

since renal clearance plays a large role in magnesium homeostasis, the _____ excretion of magnesium is also a useful index of magnesium deficiency or excess

Answer 8

urinary

Question 9

On the lab test performed during our laboratory, what are the reagent we combine?

Answer 9

magnesium and xylidyl blue-1 under ALKALINE CONDITION

Question 10

combining magnesium and xylidyl blue will give us water soluble _______

Answer 10

red-purple chelate

Question 11

we perform the activity at what wavelength

Answer 11

520 mn

Question 12

Interference from calcium is prevented by the presence of ____ which completely masks a similar colored calcium chelate

Answer 12

EGTA

Question 13

the magnesium chelate color is STABLE, and the assay is not subject to interferences from other inorganic ions

true or false

Answer 13

true

Question 14

magnesium reagent components

Answer 14

ethanolamine 750 mmol/l
EGTA 60 mmol/l
thiomalic acid 6.7 mmol/l
xylidyl blye 110 mmol/l

Question 15

magnesium standard components

Answer 15

Aqueous solution of magnesium chloride with sodium aside as preservatives

Question 16

Both reagent and standard are stable at _____*C until the expiration date on the labels

Answer 16

2-8*C

Question 17

nm of MG determination we use in the lab

Answer 17

520 nm

Question 18

what type of specimen is the preferred specimen

Answer 18

serum

Question 19

can we use plasma here?

Answer 19

yes but avoid EDTA as anticoagulant

Question 20

why do we need to avoid EDTA?

Answer 20

gives us lower test results

Question 21

what type of urine smple is needed for Mg determination?

Answer 21

24 hr urine

Question 22

24 hr urine must be preserved with ____

Answer 22

hydrochloric acid

Question 23

24 hr urine’s pH must be adjusted to

Answer 23

3-4

Question 24

24 hr urine must be diluted __ before analysis

Answer 24

1 part urine with 4 parts distilled water before analysis

Question 25

stability of serum and plasma in 2-8*C

Answer 25

7 days

Question 26

stability of serum and plasma in -20*C

Answer 26

1 month

Question 27

stability of treated urine in 2-8*C

Answer 27

7 days as well same as plasma

Question 28

interferences for Mg determination

Answer 28

use of EDTA hemolysis bilirubin up to 20 mg/dl lipemic serum contaminated glassware

Question 29

why hemolysis is must be avoided

Answer 29

rbc contain higher levels of magnesium

Question 30

is the greatest source of error

Answer 30

contaminated glassware

Question 31

since contaminated is the greatest source of error in Mg Determination it is recommended to employ ___ in the procedure

Answer 31

use disposable tubes and pipette tips

Question 32

reagent blank reagent - standard- sample

Answer 32

reagent blank reagent - 1 ml standard- 0 sample - 0

Question 33

standard blank reagent - standard- sample -

Answer 33

standard blank reagent - 1 ml standard- 0.01 ml sample - 0

Question 34

sample reagent - standard- sample -

Answer 34

reagent - 1 ml standard- 0 sample - 0.01 ml

Question 35

what should we do if the instrument requires volumes greater than 1 ml

Answer 35

volumes may be doubled

Question 36

step after preparing solutions needed

Answer 36

incubate the cuvettes at 37*C for 5 minutes

Question 37

after incubating at 37*C we must run the test at 520 nm within _______

Answer 37

1 hr

Question 38

formula for plasma or serum (mEq/L)

Answer 38

(Au / As) * 2

Question 39

formula for urine magnesium (mEq/L)

Answer 39

(Au / As) * 2*5 (Au / As) * 10

Question 40

samples having magnesium values greater than ____ are diluted 1:2 (1+1) with distilled water, the assay repeated and results multiplied factor of 2

Answer 40

4.3 mEq/L

Question 41

serum or plasma ref range

Answer 41

1.3-2.1 mEq/L

Question 42

24 hr urine ref range

Answer 42

6 - 10 - mEq/L