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Health Protocols

Blood Testing

The Risk Of Following Standard Reference Ranges

Standard laboratory reference ranges represent average populations and not optimal levels. In the 1960s, for instance, the upper reference range for cholesterol was 300 mg/dL (milligrams per deciliter). This number was based on a statistical calculation indicating that it was “normal” to have total cholesterol levels as high as 300 mg/dL. Of course, it was also considered “normal” for men to have fatal heart attacks at a relatively young age. As greater knowledge accumulated about the risk of heart attack and high cholesterol, the upper limit reference range has gradually dropped to 200 mg/dL (American Family Physician 2001; ADVANCEDATA 1977).

Blood test reference ranges are not the only measures that fail to provide physicians and patients with optimal numbers. For example, high blood pressure (hypertension) is defined medically as a blood pressure reading of 140/90 (read as “140 over 90”) or greater. However, a diastolic blood pressure reading (the second number in a blood pressure reading—90 in this example) higher than 80 mmHg (millimeters of mercury) is associated with an increased risk of stroke. A high percentage of people older than age 60 have diastolic readings higher than 80 mmHg, and this is the age group most vulnerable to stroke (Hansson 1998). If your physician checks your blood pressure and says it is “normal,” Life Extension advises you to ask what the optimal range is. Optimal blood pressure is defined as 115/75. In fact, the risk of cardiovascular disease doubles with each increase of 20/10 mmHg, starting at 115/75 mmHg. It is important to know that midlife hypertension predisposes people to stroke later in life, so keeping blood pressure readings within optimal ranges is important at any age.

Standard Hormone Reference Ranges May Be Antiquated

Conventional medicine tends to neglect the hormone imbalances that develop in both men and women as they grow older. The result is that aging people suffer a variety of miseries that are correctable and preventable if simple hormone adjustments are made.

Aging men, for instance, often suffer from excess production of insulin and estrogen, with simultaneous deficiencies of free testosterone and dehydroepiandrosterone (DHEA). The standard reference ranges for all four of these hormones are so wide that most men would fall into the so-called normal category. Standard reference ranges indicate that dangerously high insulin and estrogen levels are “normal” in older men (but so are heart attack, stroke, cancer, benign prostate enlargement, weight gain, type II diabetes, kidney impairment, and a host of other diseases that are associated with excess insulin and estrogen). The same standard reference ranges for free testosterone and DHEA show that very low levels are perfectly “normal” for aging men. It is no coincidence that aging men with low levels of testosterone and DHEA have high rates of depression, memory loss, atherosclerosis, senility, impotency, cholesterol, abdominal obesity, fatigue, and many other diseases related to low blood levels of testosterone and DHEA (Shippen 2001; Tan 2001; Janowsky 2000; Barrett-Connor 1999; Rabkin 1999; Schweiger 1999; Seidman 1999; Shackman 1999; Wright 1999; Gooren 1998; Gelfand 1997; Phillips 1994; Tenover 1992).

Standard reference ranges have failed aging people because these reference ranges are adjusted to reflect age. Since it is normal for an aging person to have imbalances of critical hormones, standard laboratory reference ranges do not flag dangerously high levels of estrogen and insulin or deficient levels of testosterone, thyroid, and DHEA. The following table compares standard and optimal hormone and TSH blood reference ranges for 60-year-old men.


Standard Reference Range

Life Extension’s Optimal Range


51.7–295.0 µg/dL

350–500 µg/dL

Insulin (fasting)

2.6–24.9 µIU/mL

< 5 µIU/mL

Free testosterone

6.6–18.1 pg/mL

20–25 pg/mL


< 54 pg/mL

20–30 pg/mL

Thyroid stimulating Hormone

0.45–4.50 µIU/mL

1–2 µIU/mL

Defying The Reference Ranges

Traditional medical thinking accepts that imbalances of life-sustaining hormones are normal in aging people. Traditional practitioners almost never test hormone levels because they think that nothing should be done to restore hormone profiles to youthful ranges. For more specific information on optimizing your hormone levels, turn to the following protocols: Male Hormone Restoration, Female Hormone Restoration, Thyroid Regulation, and DHEA Restoration Therapy.