Postural Pseudoanemia in Long-Term Care Facilities: Low hemoglobin in the morning, physicians taking warning!
American Geriatric Society Annual Meeting 2013, Journal of the American Geriatrics Society 61: Suppl. 1 S70.
Background: Anemia is very common in the geriatric population; several studies have shown that the prevalence of anemia increases with advancing in age, the increase start at the age of 65 and rises sharply after the age of 80. The prevalence of anemia is lower in men than women before the age of 55; after this age the prevalence in higher in men than women. To diagnose anemia, physicians rely heavily on the complete blood count (CBC) and specifically hemoglobin and hematocrit, which are affected by several factors: ethnic background, gender, altitude, heavy smoking and physiologic fluctuation of plasma volume. It has been shown that posture can cause change in the results for some blood indices, few reports have been published in relation to this issue.
Design: CBC specimens were collected from 64 residents in Long-Term Care Facilities very early in the morning while the patients were still in bed. Another set of CBC specimens were collected from the same patients in the afternoon. The patients’ position was noted, and CBC results were collected using Coulter LH 780 impedance /cell sizing counter. Statistic calculations were done using Statistica and Analyse-it. We compared white blood cell, red blood cell, hemoglobin, hematocrit, RDW, platelets and MCV between the morning and afternoon draws; we consider any P<0.05 to be statistically different.
Results: morning specimens had lower results than afternoon specimens for white blood cells, red blood cells, hemoglobin, hematocrit and platelets with P< 0.0001; MCV and RDW were not statistically different.
Conclusion: Our results confirm the notion that a change in posture causes changes in some of the blood indices; posture changes the hydrostatic pressure which leads to the change in the movement of fluid between interstitial space and intravascular and causes physiological fluctuation in blood volume. Physicians should give more attention to this fact, especially in severely anemic patients, where the difference in posture may alter the hemoglobin result and a decision made as to indicating the need for more aggressive treatment (blood transfusion).