Diabetes Mellitus:- Part 3 – Glucose after 2 hours of meal (postprandial glucose level)

Glucose after 2 hours (Postprandial glucose)

Sample for blood glucose

1. The test is done on the serum of patients or oxalate blood.
   • When the test is done on the serum, the serum should be separated within 30 minutes of collection.
2. The serum can be stored at 25° C for 8 hours and 72 hours at 4 °C.
3. Oxalate blood can also be used. Preservative sodium fluoride may be added.
   • The plasma can be stored at 25 °C for 24 hours (with preservative sodium fluoride).

Precautions

1. In the case of fluoride as a preservative, a decrease of 9 mg/dL is seen during the first 2 hours.
2. The whole blood glucose level is 90% of the plasma glucose.

Pathophysiology of glucose

1. Carbohydrate metabolism and interaction between carbohydrates, fats, and proteins. This interaction is important for our body to control glucose levels.
   

   Diabetes mellitus and insulin action

   

   Diabetes mellitus and insulin action

   

   Glucose level is regulated by insulin and glucagon

Definition of 2 hours of glucose level (postprandial glucose) :

1. It will give the body glucose tolerance 2 hours after the meal.
2. Meal acts as a glucose challenge for body metabolism.
3. Insulin is secreted in response to increased glucose levels due to food intake.
4. Blood glucose will be normal within 2 hours.
5. In diabetic patients, glucose levels will remain elevated.

Interpretation of postprandial or 2 hours of glucose:

1. Postprandial glucose level is a screening test for DM.
2. If glucose level is >140 mg/dL and <200 mg/dL, then GTT (glucose tolerance test) is advised.
3. If level after 2 hours = >200 mg/dL,  diabetes mellitus is confirmed.
4. Advise HbA1c for further evaluation.

Normal 2 hours (postprandial) glucose level:

Source 1

• <120 mg/dL
  • To convert into SI unit x 0.0555 = mmol/L

Source 2

1. 0 to 50 years = < 140 mg/dl (<7.7 mmol/L)
   1. And some believes <120 mg/dl ( < 6.66 mmol/L).
2. For people age 50 and younger = < 140 mg/dL (7.8 mmol/L).
3. For people ages 50 – 60 = <150 mg/dL (8.3 mmol/L).
4. For people aged 60 and older = <160 mg/dL (8.9 mmol/L)

2 hours glucose (postprandial)level:

1. Normal = <140 mg/dL.
2. Impaired glucose tolerance (IGT) = 140 to 199 mg/dL
3. Diabetes mellitus = ≥200 mg/dL

The latest criteria for Diabetes Mellitus:

1. The level of 200 mg/dl or
   1. Above 200 mg/dl after 75 grams of glucose overload or
2. Two casual glucose readings of 200 mg/dl or above are labeled as Diabetic patients.
   • This test is not recommended because of the many factors influencing the result.

• Please, for more details on Glucose, see in Glucose fasting level.

Questions and answers: