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

Sample

1. The test is done on the serum of patients or oxalate blood.
   • When the test is done on 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 (when there is 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

1. Carbohydrate metabolism, and interaction between carbohydrates, fats, and proteins.
   

   Glucose metabolism and TCA cycle

2. Definition of 2 hours of glucose level:
   2. It will give you the glucose tolerance of the body after 2 hours of a meal.
   3. Meal acts as a glucose challenge for body metabolism.
   4. Insulin is secreted in response to increase glucose levels that are due to food intake.
   5. Blood glucose will be normal within 2 hours.
      

      Glucose and insulin production

3. In diabetic patients, glucose level will remain elevated.
4. Postprandial glucose level is a screening test for DM.
5. If glucose level is >140 mg/dL and <200 mg/dL, then GTT (glucose tolerance test) is advised.
6. If level after 2 hours = >200 mg/dL  diabetes mellitus is confirmed.
7. 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)

The latest criteria for Diabetes Mellitus:

1. The level of 200 mg/dl or
   1. Above 200 mg/dl after 75 gram of glucose overload or
2. Two casual reading of glucose 200 mg/dl or above is labeled as a Diabetic patient.
   • This test is not recommended because of the many factors that influence the result.

Diagnosis	Fasting glucose level	Random glucose level	2-hour glucose level (in OGTT)	HbA1c
Prediabetics	100 to 125 mg/dL	140 to 199 mg/dL	140 to 199 mg/dL	5.7 to 6.4%
Diabetes mellitus	> 126 mg/dL	>200 mg/dL	>200 mg/dL	>6.5%

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

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