Answers to Quiz

Let us review the quiz................. :)

1. Insulin is a hormone that has effects on the body's metabolism.

2. Insulin stores glucose in the blood as glycogen.

3. When testing for insulin RIA is used to give a quantitative assay.

4. Is fasting required prior to testing? YES or NO.

5. Insulin stops the usage of fat as an energy source.


A -- increased insulin level

B -- decreased insulin level

6. A Insulinoma

7. A untreated Type 2 Diabetes mellitus

8. B severe Type 1 Diabetes mellitus

9. A Acromegaly

10. A Cushing's Syndrome


Case Study

1. Other tests such as OGTT (Oral Glucose Tolerance test), FBS (Fasting Blood Sugar), RBS (Random Blood Sugar) could be used to diagnose increased sugar levels, like diabetes, which is the cause of the positive Benedict's and Fehling's tests.

2. Other tests Other tests such as OGTT (Oral Glucose Tolerance test), FBS (Fasting Blood Sugar), RBS (Random Blood Sugar) could be used to diagnose increased sugar levels, like diabetes. In this specific case, diabetes mellitus is diagnosed from the given laboratory tests.

Quiz: Insulin

**lets keep your brain cells working with this Insulin quiz.:)


1. _______ is a hormone that has effects on the body's metabolism.

2. Insulin stores glucose in the blood as ________.

3. When testing for insulin RIA is used to give a ___________ assay.

4. Is fasting required prior to testing? YES or NO.

5._______ stops the usage of fat as an energy source.

A -- increased insulin level
B -- decreased insulin level

6. Insulinoma

7. untreated Type 2 Diabetes mellitus

8. severe Type 1 Diabetes mellitus

9. Acromegaly

10. Cushing's Syndrome





Case Study( 5pts per case)




Case 1

Marco, a teenager loves to eat and is a little overweight. Lately he noticed that he urinates more frequently, thirsts and hungers more frequently than he usually did, and had lower back pain. He decided to visit the doctor. He was subjected to lab tests, the results are as follows:



Urinalysis

(+) Benedict's Test

(+) Fehling's Test

Protein - trace



What other tests should be done? Why? What brings about a positive Benedicts and Fehling's test?





Case 2



A 60 year old lady subjected herself to laboratory tests, the results are as follows:

RESULTS:

FBS: 215

HDL: 20.47

LDL: 100.36

BUN: 12

What other tests should be done? What can be diagnosed from these results?

Insulin

INSULIN

What is Insulin?


Insulin is defined as “a hormone that has extensive effects on metabolism and other body functions, such as vascular compliance. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle, and stopping use of fat as an energy source.” (Wikipedia 2009)

Photo by: http://www.chemlin.net/news/2006/oct2006/human-insulin-degrading-enzyme.htm

Testing for Insulin Levels

Testing for insulin is done using a radioimmunoassay that gives a quantitative analysis of serum insulin levels.

Patient Preparation:

• Patient should fast from all foods and fluids except water for 10-12 hours prior to testing.
  

Procedure and Posttest Care:

1. Obtain 5mL of blood from a fasting person, serum is preferred. Observe standard precautions.


2. Instruct patient that he/she may resume from his/her usual activities after the test.

Interfering Factors:

1. Oral hypoglycemic agent ingestion or injection causes elevated insulin levels.


2. Oral contaceptives and other drugs cause falsely elevated values.


3. Recently administered radioisotopes affect test results.


4. In the second to third trimester of pregnancy, there is a relative insulin resistance with a progressive decrease of plasma glucose and immunoreactive insulin.


5. Agitation and stress.


6. Hemolysis due to rough handling of the sample.
   

Reference Values:

NORMAL:

Immunoreactive
Adults: 0-35 IU/mL or 0-243 pmol/L

Children: 0-10 IU/mL or 0-69 pmol/L

Free
Adults: 0-17 IU/mL or 0-118 pmol/L

Children (prepubertal): 0-13 IU/mL or 0-90 pmol/L

Clinical Implications:

1. Increased insulin levels:

• Insulinoma
  
• Type 2 diabetes mellitus, untreated


• Acromegaly


• Cushing's syndrome


• Endogenous administration of insulin (factitious hypoglycemia)


• Obesity (most common cause)


• Pancreatic islet cell hyperplasia
  

2. Decreased insulin levels:

• Type 1 diabetes mellitus (severe)
  
• hypopituitarism
  

References:

• A Manual of Laboratory and Diagnostic Tests 7th Edition By: Frances Fischbach
  
• Prof. Guide to Diagnostic Tests
  
• http://wikipedia.com