From the Guidelines
A red blood cell (RBC) count of 3.95 million cells per microliter is slightly below the normal range for adults, indicating a potential mild anemia, and further investigation is necessary to determine the cause, particularly iron deficiency, which is common in female athletes with a prevalence of 15-35% 1. This mild decrease may be close to the lower end of normal for women, but it's essential to evaluate the patient's overall health and athletic performance. Important follow-up tests include a complete blood count (CBC) with hemoglobin and hematocrit levels, iron studies, vitamin B12 and folate levels, and reticulocyte count, as iron deficiency and anemia are not synonymous, and athletes can be iron deficient without being anemic 1. Some key points to consider in the evaluation and management of this patient include:
- Iron deficiency is a common condition in female athletes, with estimates of prevalence varying from 15 to 35% 1
- A full iron panel, including ferritin, serum iron, transferrin, transferrin saturation, and total iron binding capacity, is necessary to evaluate iron deficiency 1
- Athletes with restrictive diets, high amounts of repetitive ground strikes, endurance training, and heavy menstrual bleeding are at higher risk of iron deficiency 1
- Iron from meat (heme iron) is better absorbed than plant-based iron (non-heme), and athletes with restrictive diets should consult a sports dietitian to optimize their daily nutrition plans for iron intake 1
- The current USDA recommended daily allowance for iron is 15-18 mg/day, but athletes with risk factors may require higher levels of iron intake 1.
From the Research
Red Blood Cell Count
- A red blood cell (RBC) count of 3.95 is considered low, as it falls below the normal range for adults 2.
- Low RBC counts can be caused by various factors, including iron deficiency anemia, vitamin B12 deficiency, and folate deficiency 3, 4.
- Iron deficiency anemia is the most common cause of low RBC counts, and it can be managed with iron therapy 4.
- Vitamin B12 and folate deficiencies can also cause low RBC counts, and oral vitamin B12 can be an effective treatment for vitamin B12 deficiency anemia 4.
Diagnostic Tests
- A full blood count (FBC) is the first laboratory test used to diagnose anemia, and it can help identify the underlying cause of low RBC counts 3.
- The FBC test measures various parameters, including hemoglobin, mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) 5.
- The platelet count/MCH ratio can be used to differentiate between iron deficiency anemia and combined iron and vitamin B12 deficiency anemia 5.
Reference Values
- Normal RBC count reference values vary by geographical area, and a study in Chinese presenile women found significant correlations between geographical factors and RBC counts 2.
- The study developed a regression equation to estimate normal RBC reference values in presenile women based on geographical area 2.
Environmental Factors
- Exposure to environmental pollutants, such as metals and perfluoroalkyl substances (PFAS), has been associated with lower RBC folate concentrations 6.
- A study using data from the US National Health and Nutrition Examination Survey (2007-2016) found inverse associations between 12 environmental chemicals and RBC folate concentrations 6.