### Description

Residence at a high altitude exposes a person to relative hypoxia compared to what a person residing at sea level experiences. This results in a slightly higher hemoglobin level in the blood for a person residing at altitude as compared to that of a person residing at sea level. The following analysis was based on patient data collected in the Andes and coastal regions of Ecuador.

hemoglobin at altitude in g/L =

= (6.83 * (EXP(0.000445 * (altitude in meters)))) + 113.3

hematocrit at altitude in percent =

= (0.449 * (EXP(0.000859 * (altitude in meters)))) + 35.6

At sea level, the ratio of hemoglobin (in g/L) divided by hematocrit (in percent) is 3.34 (which is the ratio if enter 0 for altitude in the above equations).

Correction of a hemoglobin value can be performed using the following table:

(1) for a value at an altitude, the comparable value at sea level can be estimated by subtracting the correction factor

(2) for a value at sea level, the comparable value at altitude can be estimated by adding the correction fraction.

 Altitude in meters Correction to Hemoglobin in g/L 0 0 100 0 200 1 300 1 400 1 500 2 600 2 700 3 800 3 900 3 1000 4 1100 4 1200 5 1300 5 1400 6 1500 7 1600 7 1700 8 1800 8 1900 9 2000 10 2100 11 2200 11 2300 12 2400 13 2500 14 2600 15 2700 16 2800 17 2900 18 3000 19 3100 20 3200 22 3300 23 3400 24 3500 26

from Table 2, page 629

If this data is analyzed in JMP, the correction can be estimated as:

correction in g/L =

= (0.0000016 * ((altitude in meters) ^2)) + (0.0016113 * (altitude in meters)) + 0.4359886