The phase angle can be calculated from measurements taken with Bioelectrical Impedance Analysis (BIA). This correlates with body composition, nutritional status and prognosis for a number of conditions.
Parameters:
(1) reactance in Ohms
(2) resistance in Ohms
phase angle in degrees =
= arctan ((reactance) / (resistance)) * 180 / PI()
where:
• Arctan returns a value in radians.
• The 180/PI() converts radians to degrees.
• A calculator set to degrees does not require the conversion step.
Impression:
• A low phase angle is associated with a poor outcome in a number of conditions (such as breast cancer, lung cancer, COPD, cirrhosis, AIDS).
• Gupta et al found that women with breast cancer and a phase angle <= 5.6 degrees had a worse prognosis.
Reference ranges from Barbosa-Silva et al
Age in Years
Female 5th Percentile
Female 95th Percentile
Male 5th Percentile
Male 95th Percentile
18 to 20
5.9
8.9
7.0
8.8
20 to 29
5.6
8.6
6.8
9.2
30 to 39
5.6
8.4
6.6
9.5
40 to 49
5.6
8.3
6.5
9.0
50 to 59
5.5
8.0
6.1
8.7
60 to 69
4.7
7.5
5.4
8.9
>= 70
4.2
7.0
4.8
8.0
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