Patient compliance with diet restrictions prior to sample collection is essential for the accuracy of test results. What a patient consumes prior to sample collection can impact analytes and subsequent test results. Fasting (no eating) prior to sample collection is the most common requirement.
Nutrients from food and drink are absorbed through the intestinal tract and pass into the blood. Blood serves as the delivery system for the nutrients originating from dietary sources to target cells and tissues. Depending on the quantity of foods consumed, the content of the food products, and the time between consumption and sample collection, certain analytes or measurands are directly affected.
Reference intervals for analytes are usually based on a fasting state, minimizing the direct effect of what has been recently consumed on the analysis and subsequent clinical interpretation.
The required period of fasting may vary but is generally in the range of 8 to 12 hours prior to sample collection.
Listed below are common analytes for which fasting is often required:
- Glucose
- Triglycerides
- Insulin
- Iron
