Anesthesia Technologist Practice Exam

How can the Hematocrit be calculated from Hemoglobin levels?

1. By adding 10 to the Hemoglobin

2. By multiplying the Hemoglobin by 3

3. By dividing the Hemoglobin by 3

4. By subtracting 5 from the Hemoglobin

The correct answer is: By multiplying the Hemoglobin by 3

The calculation of hematocrit from hemoglobin levels relies on a well-established clinical relationship between these two parameters, which are both measures of red blood cell content in the blood. Hematocrit is the volume percentage of red blood cells in blood, while hemoglobin measures the oxygen-carrying component within those red blood cells. Multiplying hemoglobin levels by three provides an estimation of hematocrit, as the average red blood cell contains approximately three times more hemoglobin than the volume of blood cells it contributes to. This reflects the fact that while hemoglobin concentration is measured in grams per deciliter, hematocrit is expressed as a percentage. Therefore, the relationship holds that if you have a hemoglobin value, you can estimate the hematocrit by applying this multiplication factor. For instance, if a patient's hemoglobin is 15 grams per deciliter, multiplying by three gives an approximate hematocrit of 45%, which is consistent with normal physiological values. This formula is particularly useful in clinical settings for quickly estimating hematocrit without the need for additional testing, streamlining patient assessment processes.