Saturday, April 16, 2016


I. Introduction

Sodium is the most abundant cation in the extra cellular fluid (ECF), represented 90% of all extracellular cation and largely determines the osmolality of the plasma. Active transport system at the cellular membrane maintain high Na+ levels in the ECF, where as K+ is concentrated with in the cell. 
Changes in extracellular Na+ concentration result in increase or decreases in the osmolality of the ECF, which in turn, influence the distribution of body water. It is therefore related in regulation of water balance as well as blood volume in the body.

Normally, serum Na+ concentration varies between 136 and 145 mmol/L in healthy individuals. The normal daily intake of Na+ is 100-250 mmol. Ordinarily, the amount of Na+ loss is balance by the daily intake.

Determination of Na+ level is of vital key in the proper diagnosis and treatment of diseases associated with it. 

A decrease in serum sodium level, termed as “hyponatremia” is usually seen in hypoadrenalism, potassium deficiency, diuretic use, ketonuria, salt-losing nephropathy, prolonged vomiting, diarrhea, renal failure, hepatic cirrhosis, congestion heart failure (CHF) and diabetic ketoacidosis. 

Whereas, an increase in serum sodium level, termed as “hypernatremia” is seen in profuse sweating, severe burns, dehydration, malnutririon, edema, ascitis in chronic failure, uncontrolled diabetes, and nephritic syndrome.

II. Procedure/ Flowchart of the experiment
Pipet out 0.1ml serum and place in a test tube
Add 3ml base reagent followed by 3 drops of color reagent
Mix thoroughly for 30sec. and let it stand for 30min. at room temperature
Read at 550nm against a water blank
Interpret results obtained


Place 0.1 ml of unhemolyzed serum into 16X100 mm test tubes.

Label tube as test serum standard.

Add 2.5 ml of Sodium Base Reagent into the tubes.

Place 3 gtt of Sodium Color Reagent.

Mix well and read at 550 nm against a water blank.

III. Results and Discussion

Concentration of the unknown: 531.62 mmol/L
Normal range for serum specimen: 134-148 mmol/L
Interpretation: “Above normal range”

The interpretation of the result obtained was above normal range because it exceeds the maximum Na+ level that a normal adult could have.

IV. Intrinsic and Extrinsic factors

The probable sources of errors are:
-          contaminated tubes or cuvets
-          contaminated serum
-          ineffective reagent
-          under/ over centrifugation
-          prolonged standing of specimen
-          misreading of result by spectrophotometer