From the Guidelines
A hematocrit of 34-35% in an African American female over a 4-year period likely represents her normal baseline rather than anemia requiring intervention. For African American women, normal hematocrit values are typically 1-2% lower than reference ranges established primarily in white populations, with 34-35% often falling within the normal adjusted range, as suggested by the Institute of Medicine's recommendation to lower Hb concentration and Hct cutoff values for black adults by 0.8 g/dL and 2%, respectively 1. No specific treatment is needed if she is asymptomatic and this represents a stable value. However, it would be prudent to ensure iron studies (ferritin, iron, TIBC) have been checked at least once to rule out iron deficiency, which is common in women of reproductive age.
- A complete blood count with indices (MCV, MCH, MCHC) should be reviewed to ensure normal red cell morphology.
- If she develops symptoms like fatigue, shortness of breath, or if the hematocrit drops further, additional evaluation would be warranted. The lower hematocrit in African Americans is attributed to genetic factors affecting hemoglobin production, particularly the higher prevalence of alpha thalassemia trait and other hemoglobinopathies in this population, which should be considered when interpreting CBC results, as noted in the study by the Centers for Disease Control and Prevention 1.
From the Research
Hematocrit Trends in African American Females
- A hematocrit level of 34-35 over 4 years in an African American female may not necessarily be indicative of anemia, as reference intervals for hemoglobin and hematocrit can vary by ethnicity 2, 3, 4.
- Studies have shown that African American women tend to have lower hemoglobin and hematocrit levels compared to white women, even in the absence of iron deficiency or other underlying conditions 2, 3, 4.
- A study published in 2005 found that 19.8% of African American women would be classified as "anemic" based on standard reference intervals, compared to 5.3% of white women 2.
- Another study published in 2019 found that African women had lower mean hemoglobin and hematocrit levels compared to Caucasian women, even in pregnancy 4.
Complete Blood Cell Count (CBC) Evaluation
- A complete blood cell count (CBC) is an essential tool in evaluating suspected anemia, and can provide important clues to the classification and cause of anemia 5.
- The CBC should be carefully examined, including the mean corpuscular volume (MCV), to determine the underlying cause of anemia 5.
- Supplemental tests, such as a peripheral blood smear, reticulocyte count, and iron panel, may also be necessary to determine the cause of anemia 5.
Ethnic-Specific Reference Intervals
- Ethnic-specific reference intervals for white blood cell count and absolute neutrophil count have been established, highlighting the importance of considering ethnicity when interpreting laboratory results 6.
- Similar ethnic-specific reference intervals for hemoglobin and hematocrit may also be necessary to accurately diagnose and treat anemia in different populations 4.
- The use of ethnic-specific reference intervals can help reduce misdiagnosis and inappropriate treatment of anemia in African American women 2, 4.