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High Elevation and Blood Work: Why it Matters

Aug 2, 2021

High Elevation and Blood Work:

Why it Matters

Do you see clients with elevated red blood cells (RBC), hemoglobin (HGB), and hematocrit (HCT) and automatically assume dehydration or asthma? Well, if your client lives at an elevation above 3,280 feet—think of cities like Denver, Reno, and Santa Fe—you may need to reconsider.

Elevation influences blood work. And, accurate analysis of these critical red blood cell values influences your clients’ outcomes. There are over 6 million people in the United States who live at elevations above 3,280 feet. So, there’s a good chance you already have or will soon have a client from one of these cities, and you should understand the adjustments you need to make to properly interpret their blood work.


First, let’s do a quick review of RBC, HGB, and HCT.

Red blood cells, or erythrocytes, are incredibly unique discoid-shaped cells with no nucleus and no mitochondria. Their shape and lack of nucleus allow for maximum surface area and pliability—the perfect form for their function of transporting oxygen and carbon dioxide through small spaces in the cardiovascular and pulmonary systems (1).

Hemoglobin is a four-part protein, or tetramer, consisting of four globin chains. Each chain contains a small metal complex called heme. Iron is an integral part of the heme complex that binds and unbinds oxygen for transportation throughout the body (2).

High elevation and bloodwork

Hematocrit is a measurement of the volume of red blood cells in the total blood and is sometimes referred to as packed cell volume (PCV). Whole blood is first centrifuged. Then, the percentage of the total volume occupied by the now “packed” RBCs is measured (3). Interestingly, the name hematocrit comes from the English “hemato”, meaning related to the blood and Greek “krites”, meaning separate or judge. And, in fact, both hematocrit and hemoglobin are the most reliable values for judging the possibility of anemia.

For a review of all seven RBC-related blood work markers on the CBC, click here.

Blood work changes at high elevations.

Blood work analysis performed for clients living in high elevation cities like Denver and Santa Fe will be inaccurate if the ranges for red blood cells, hemoglobin, and hematocrit are not adjusted upward.

The barometric pressure of the atmosphere decreases with each incremental increase in elevation. This increase causes oxygen molecules in the air to get farther apart. As a result, the oxygen content of each breath is reduced incrementally the higher up one lives from sea level. This leads to persistent hypoxia.

Ultimately, people living at higher elevations take in less oxygen with each breath. Their bodies overcompensate by generating more red blood cells to capture more oxygen. This means their normal levels of RBC, HGB, and HCT are higher than those living closer to sea level.

Adjust reference ranges for accurate blood work analysis.

Do you currently adjust RBC, HGB, and HCT ranges upward for clients who live at higher elevations? If not, you might be missing out on identifying anemia as a possible root cause of fatigue. Or, you may incorrectly think dehydration or asthma are conditions your clients need to address.

LabSmarts automatically adjusts reference ranges upward for RBCs, HGB, and HCT for clients living at elevations above 3,280 feet.

Our software uses correction factors recommended by the World Health Organization according to evidence-based elevation increments (4,5). To learn more, click here.

This short video highlights the importance of adjusting RBC-reference ranges upward for high elevation and shows how LabSmarts quickly and easily does this for you.


  1. Barbalato L, Pillarisetty LS. Histology, Red Blood Cell. In: StatPearls. StatPearls Publishing; 2021.
  2. Farid Y, Bowman NS, Lecat P. Biochemistry, Hemoglobin Synthesis. In: StatPearls. StatPearls Publishing; 2021. 
  3. Mondal H, Budh DP. Hematocrit. In: StatPearls. StatPearls Publishing; 2021. 
  4. WHO | Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. WHO> 
  5. Sullivan KM, Mei Z, Grummer-Strawn L, Parvanta I. Haemoglobin adjustments to define anaemia. Trop Med Int Health. 2008;13(10):1267-1271. 

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