ABT reference ranges

Red Blood Cell Panel

  1. Higher hemoglobin in rowers than the general population
  2. The Influence of Training Load on Hematological Athlete Biological Passport Variables in Elite Cyclists
  3. Greater erythrocyte deformability in world-class endurance athletes
  4. Training-induced annual changes in red blood cell profile in highly-trained endurance and speed-power athletes
  5. Red Blood Cells in Sports: Effects of Exercise and Training on Oxygen Supply by Red Blood Cells
  6. Reticulocytes in Sports Medicine: An Update


Red blood cell variation is observed among athletes during different stages of the season. Parameters such as hematocrit, hemoglobin, MCV, and reticulocytes can differ for the athletic population as compared to a sedentary population.  Based on published research, higher hemoglobin and hematocrit levels can be beneficial for athletic performance. Lower levels can be a sign of micronutrient deficiencies or anemia. Athletes can be at higher risk of iron deficiency anemia. Our optimal levels in this panel are based on published research that prioritizes the prevention of reduced hemoglobin and hematocrit levels.

White Blood Cells

  1. Lower White Blood Cell Counts in Elite Athletes Training for Highly Aerobic Sports
  2. Association of physical activity and sedentary time with blood cell counts: National Health and Nutrition Survey 2003-2006
  3. Enhanced Strength and Sprint Levels, and Changes in Blood Parameters during a Complete Athletics Season in 800 m High-Level Athletes
  4. Biochemical and Immunological Markers of Over-Training


White blood cells at the low end of the reference range may represent adaptive changes to training. Our reference range aims to point out that lower white blood cell counts within the normal range for athletes are consistent with published research. 


  1. Iron deficiency in sports – definition, influence on performance and therapy. UpToDate
  2. Iron considerations for the athlete: a narrative review
  3. Absolute and functional iron deficiency in professional athletes during training and recovery
  4. Is iron treatment beneficial in, iron-deficient but non-anaemic (IDNA) endurance athletes? A systematic review and meta-analysis


ABT ranges for serum iron and ferritin prioritize the prevention of iron deficiency with and without anemia. In addition, researchers have demonstrated that athletes’ physiological demand for iron exceeds the general population, and the prevalence of iron deficiency is higher in the athletic population. Therefore, a higher ferritin level in the blood ( within normal ranges) can help prevent iron deficiency and may aid in athletic performance.


  1. Does Replacing Sodium Excreted in Sweat Attenuate the Health Benefits of Physical Activity?
  2. Exercise-Associated Hyponatremia in Endurance and Ultra-Endurance Performance–Aspects of Sex, Race Location, Ambient Temperature, Sports Discipline, and Length of Performance: A Narrative Review
  3. Diagnosis and prevention of hyponatremia at an ultradistance triathlon.


ABT ranges for serum sodium prioritize the prevention of hyponatremia longitudinally over a training and competition season and arriving at race day with sodium levels at, or above, a range in which a decrease of 4-5mmol/l is still within normonatremia range. 

Vitamin B12

  1. Vitamin B12 Status and Optimal Range for Hemoglobin Formation in Elite Athletes
  2. Female athletes: a population at risk of vitamin and mineral deficiencies affecting health and performance
  3. Altered vitamin B12 status in recreational endurance athletes


Altered vitamin B12 concentrations can reduce hemoglobin levels and impact athletic performance. ABT ranges for vitamin B12 prioritize the prevention of vitamin B12 deficiency and promote healthy hemoglobin levels. In addition, studies suggest that concentrations higher than established lab ranges may be beneficial for the athlete.


  1. Iron, folate and vitamin B12 status of Ethiopian professional runners
  2. Effect of folic acid supplementation on homocysteine concentration and association with training in handball players
  3. The effects of exercise training and acute exercise duration on plasma folate and vitamin B12
  4. B-vitamins and exercise: does exercise alter requirements?


Folate plays an important role in red blood cell production and tissue repair. It’s also an important component of cell division, particularly in cells with higher turnover rates. In athletes, red blood cells have a higher turnover rate due to the stresses of training. Lower levels of folate in athletes were found in several studies, suggesting that higher folate intake may be beneficial for athletes. Therefore, higher folate levels are desirable due to higher turnover rates of red blood cells and keeping up with the demands of training. 

Vitamin D

  1. Vitamin D for Health Professionals – National Institute of Health 
  2. Vitamin D and the Athlete: Current Perspectives and New Challenges
  3. Plausible ergogenic effects of vitamin D on athletic performance and recovery
  4. Vitamin D and the Athlete: Risks, Recommendations, and Benefits


ABT ranges for vitamin D are consistent with literature-established reference ranges for athletic performance. Vitamin D deficiency levels are routinely debated in the scientific community. ABT prioritizes reducing the risk of vitamin D insufficiency and deficiency in the athletic population.


  1. https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/#h6
  2. Chronic Ingestion of Sodium and Potassium Bicarbonate, with Potassium, Magnesium and Calcium Citrate Improves Anaerobic Performance in Elite Soccer Players
  3. Excretion of Sodium, Potassium, Magnesium and Iron in Human Sweat and the Relation of Each to Balance and Requirements
  4. Plasma potassium changes with high intensity exercise. – Medbø – 1990 – The Journal of Physiology – Wiley Online Library
  5. Catecholamine Modulation of Rapid Potassium Shifts during Exercise | NEJM


Potassium is one of the body’s most important electrolytes. Nearly 70% of the potassium in the human body is found in bodily fluids including blood and sweat. Therefore if you sweat heavily, as many athletes do, potassium is lost through sweat. Potassium also increases rapidly and acutely during exercise, therefore requiring additional potassium for optimal athletic performance. Low potassium levels can reduce energy and endurance, two crucial components of athletic performance.


  1. Update on the relationship between magnesium and exercise
  2. An 8-year Analysis of Magnesium Status in Elite International Track & Field Athletes
  3. Can Magnesium Enhance Exercise Performance?


ABT ranges for serum magnesium to prioritize the prevention of hypomagnesemia and marginal magnesium deficiencies. Published literature points to the important role magnesium has in athletic performance. Our reference range aims to reduce the risk of performance-related deficits due to inadequate magnesium status. 

Testosterone  (total and free)

  1. Low testosterone in male endurance-trained distance runners: impact of years in training
  2. Hormonal Changes in High-Level Aerobic Male Athletes during a Sports Season
  3. Testosterone Induces Erythrocytosis via Increased Erythropoietin and Suppressed Hepcidin: Evidence for a New Erythropoietin/Hemoglobin Set Point
  4. Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance
  5. Serum androgen profile and physical performance in women Olympic athletes


Lower circulating testosterone concentrations can negatively impact athletic performance and recovery. ABT ranges prioritize the prevention of low testosterone through natural methods.  *note – ABT is a strong proponent of clean sport and does not endorse the use of exogenous testosterone without the supervision of a medical doctor and in adherence to anti-doping regulations.


  1. Relationships among training stress, mood, and dehydroepiandrosterone sulphate/cortisol ratio in female cyclists
  2. Effects of amount of training on the saliva concentrations of cortisol, dehydroepiandrosterone and on the dehydroepiandrosterone: cortisol concentration ratio in women over 16 weeks of training


Lower levels of DHEA, combined with other blood markers and variables can be sign of overtraining. ABT reference ranges prioritize the prevention of low DHEA-s and aiming for higher levels than lab established reference ranges. 


  1. Acute Response to Endurance Exercise Stress: Focus on Catabolic/anabolic Interplay Between Cortisol, Testosterone, and Sex Hormone Binding Globulin in Professional Athletes
  2. Blood Hormones as Markers of Training Stress and Overtraining
  3. https://labtestsonline.org/tests/sex-hormone-binding-globulin-shbg
  4. Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance

High levels of SHBG can reduce levels of circulating free testosterone and other sex hormones which can hinder athletic performance. ABT reference ranges mitigates risk of elevated SHBG by pursing a narrower reference range. 


  1. Elevated hair cortisol concentrations in an endurance athlete
  2. Exercise and circulating cortisol levels: the intensity threshold effect
  3. Role of psychological stress in cortisol recovery from exhaustive exercise among elite athletes
  4. Monitoring intensive endurance training at moderate energetic demands using resting laboratory markers failed to recognize an early overtraining stage
  5. Review Article Open Access Overtraining, Exercise, and Adrenal Insufficiency

Intensive physical training can raise cortisol levels in the athletic population. A single elevated serum cortisol concentration can be an acute response to exercise. Conversely, low cortisol levels have been linked to overtraining. ABT references range allows for a slight increase in serum cortisol concentrations and raises the lower reference point to account for the risk of cortisol suppression due to overtraining. ABT recognizes the limitation of single serum cortisol measurement. 


  1. Exercise intensity and its effects on thyroid hormones