Estimation of Blood Glucose level by Folin-Wu method

Estimation of Blood Glucose level by Folin-Wu method is one of the clinical biochemistry protocol. You can download this protocols from the given link.

Estimation of Blood Glucose level by Folin-Wu method


To estimate Glucose level in Blood by Folin-Wu method


When glucose or other reducing agents are treated with alkaline copper solution they reduce the copper with the result insoluble cuprous oxide is formed. The reaction depends on temperature, duration of heating, degree of alkalinity. The ratio of glucose to cuprous oxide form may be varied after heating far a period. The cuprous oxide form is allowed to react with phospharomolybdate to form molybdenum blue colored complex which can be read colorimetrically using red filter on at 680nm.

Estimation of Blood Glucose level by Folin-Wu method


  1. 1% Sugar solution: 1 gram of sugar is added in 100ml saturated benzoic acid.
  2. Working standard sugar solution:2 mg per 2 ml of the above solution.
  3. Alkaline copper solution:
    1. Solution A: Dissolve 2% Na2CO3 in 0.1N NaOH.
    2. Solution B:5% CuSO4 in 1% sodium potassium tartarate or Rochelle salt

Mix 50ml of solution A with 1 ml of solution B.

  1. Phosphomolybdic acid: To 35grms of moybdic acid add 5 grams of sodium tungastate, 200 ml of 10% NaOH and 200ml of water is added. It is boiled vigorously for 20-30 minutes so as to remove whole of ammonium present in molybdic acid. The solution is cooled and diluted to about 350ml and 125 ml of 85% phosphoric acid (ortho) is added and make up to 500ml with distilled water.
  2. 10% Sodium tungastate
  3. 2/3 N H2SO4


De-proteination of Blood:

1 ml of Blood is transferred to boiling tube containing 7 ml of water then 1 ml of 10% sodium tungastate is added mixed well followed by 1 ml of 2/3 N H2SO4 with shaking. It is allowed to stand for 10 minutes, it is then filtered. This filtrate is called tungastic acid blood filtrate and is taken as Test sample.

2ml of tungastic acid blood filtrate is transferred to folin-wu tube graduated at 25 ml mark and to other similar folin-wu tubes 2 ml of standard glucose solution and 2ml of water as Blank is added. To each of the three tubes 2 ml of alkaline CuSO4 is added. Now the surface of the mixture is in line with 4ml mark of the Folin-Wu tube. The folin-wu tubes are placed in boiling water bath exactly for 8 minutes. It is cooled under running water. To each of the tube 2 ml of phosphomolybdic acid solution is added. After 1 minute it is diluted with water upto the mark. The solution is transferred to a suitable tube and OD is read at 680nm.

Normal values:

  • The normal blood sugar level ranges from 8 to 120 mg / 100ml of blood
  • In mild diabetic conditions value if blood glucose from 140-300 mg / 100ml of blood and in severe diabetic conditions value is upto 1200mg / 100ml of blood have been noted.
  • Low blood sugar level values are formed in insulin administration, addison’s disease, hypoglycemia and hypopituitarism.


_______ mg of glucose is present in 100 ml of given blood sample.


Mg of glucose / 100ml of blood = mg of glucose in standard X (OD of test / OD of Standard) X 100/ 0.2

free biochemistry lectures
  • Updated July 16, 2017
Click Here to Leave a Comment Below 5 comments
Hassan A Umar

Thank you for your contribution.

Swati Shaw

Great help !
I have some basic queries :
1. what is the need of deproteinisation of blood ?
2. why blood sample which is to be deproteinised oxalated with floride ?

    Padma Sai

    The oxidizing agent used here is tartrate complex of alkaline copper(II) sulphate known as Fehling solution.This one reacts with blood proteins and may give false results so blodd is deproteinized bu tungstic acid before use


Thankx for this kind of good info. keep on posting these kind of good things


Why lower portion of follin Wu tube is rounded & narrow?


Leave a Reply: