OSMT (Ontario Society of Medical Technologists) Practice Exam

All of the following tests should be collected in a red top tube except:

1. Iron binding capacity

2. RBC fragility

3. LD, LDH

4. B 1

The correct answer is: RBC fragility

The collection of blood tests in specific types of tubes is crucial because the additives in the tubes can affect the integrity and results of the tests being performed. A red top tube is primarily used for collecting serum samples. This type of tube does not contain any additives that would interfere with tests that measure certain substances in the blood. Iron binding capacity, LD (Lactate Dehydrogenase), and B1 (a vitamin that can be measured in the serum) all require serum, which is why these tests can be collected in a red top tube. The red top tube allows blood to clot, after which the serum can be separated by centrifugation. However, RBC fragility testing typically requires whole blood or specific conditions that are not compatible with the red top tube, making it unsuitable for this test. This distinction is crucial for obtaining accurate and reliable results in hematological assessments. Thus, identifying RBC fragility as the exception highlights the importance of using appropriate specimen types for different laboratory tests to ensure optimal diagnostic outcomes.