Sodium

Question 1

Principle for Sodium

Answer 1

β-galactosidase catalyzes the conversion of o-nitrophenyl-β-D- galacatopyranoside (ONPG) to o-nitrophenol and galactose. The activity of β-galactosidase depends on the sodium concentration in the sample. The absorbance increase at 405 nm is proportional to the sodium concentration in the sample.

Question 2

Method for sodium

Answer 2

Enzymatic photometric test

Question 3

Specimen

Answer 3

Plasma or serum

Question 4

R1 for sodium

Answer 4

THAM buffer ph9.0
Chelator 0.15%
ß-galactosidase 0.01%

Question 5

R2 for sodium

Answer 5

Tham buffer ph8.8
ONPG

Question 6

Warnings and precautions for sodium

Answer 6

1. The sodium test is very susceptible to sodium contamination. The sole use of ultrapure glass ware and disposable material is strongly recommended.
2. In very rare cases, samples of patients with gammopathy might give falsified results [7].
3. Please refer to the safety data sheets and take the necessary precautions for the use of laboratory reagents. For diagnostic purposes, the results should always be assessed with the patient’s medical history, clinical examinations and other findings.

Question 7

Interfering substances

Answer 7

Ascorbic acid
Conjugated and uncojugated bilirubin
Lipemia
Hemoglobin
Calcium
Copper
Iron
Lithium
Magnesium
Potassium
Zinc

Question 8

Conversion factor for sodium

Answer 8

2.30

Question 9

Reference range for sodium

Answer 9

135-145 mmol/L

Question 10

Wavelength for sodium

Answer 10

405 nm

Question 11

Measuring range for sodium

Answer 11

100-180 mmol/L

Question 12

Limit of detection for sodium

Answer 12

42 mmol/L