Dr. Broda Barnes Basal Body Temperature Test Procedures (printed & digital), a highly accurate vintage mercury thermometer, and 1/2oz of Lugol's 5% iodine solution.  This test provides a clear picture of your thyroid gland in regards to its ability to maintain the normal body temperature of 98.6°F.  A few tenths of degrees cooler indicates inadequate thyroid function. 
 
 
 
 Barnes Thyroid Temperature Test
Shake down the thermometer the night before and place on your night table. First thing in the morning, before getting out of bed, tuck the thermometer in your armpit and lie very still for 10 minutes. 
Record your temperature on the chart below. 
Indicate the first day of your menstrual period by circling the temperature on the chart for that day. 
Indicate the last day of your menstrual period by making an “X” through the temperature on the chart. 
If the thyroid is overactive, your temperature will show 1-2 degrees above normal. If the thyroid is underactive, your temperature will show 1-2 degrees below normal.
The normal underarm temperature is between 36.6 and 36.8 degrees. If your temperature
is consistently below this level, blood tests for evaluating thyroid function are recommended. However, be aware
that these tests are
often normal even if
the thyroid gland is malfunctioning. That is because the tests
show only how much thyroid hormone is circulating in the blood and tell nothing of how well the hormones are functioning on a cellular level. Additionally, the loss of up to 70% of thyroid function may occur before blood tests become abnormal.
This test was developed by Broda O. Barnes, MD, PhD., a practicing physician in the state of Colorado. It is Dr. Barnes’ opinion that this test is superior to standard blood studies for the evaluation of thyroid function. Blood tests measure only pituitary (TSH) and T3 hormone levels, while temperature readings measure the amount of energy actually being generated in cells.