Medical Wellness7 min readFebruary 25, 2025

What Labs Should You Get Every Year? A Functional Medicine Perspective

Most annual physicals include a basic metabolic panel, CBC, and cholesterol. That is it. From a functional medicine perspective, this is the bare minimum. There is a wide gap between 'not sick' and 'optimally well,' and standard labs often miss the markers that reveal early dysfunction before it becomes disease. Here is what Devorah recommends looking at annually, and why.

Devorah, DNP, APRN, FNP-BC

Board-Certified Nurse Practitioner · Bee the NP

The standard annual labs and their limitations

A typical annual physical includes a CBC (complete blood count), CMP (comprehensive metabolic panel, including glucose, kidney, and liver markers), and a lipid panel. These are important and should not be skipped. But they have significant blind spots. A fasting glucose of 99 mg/dL is technically normal, but is trending toward insulin resistance. A total cholesterol of 195 is 'normal,' but the LDL particle size distribution, which determines cardiovascular risk more accurately, goes unmeasured. A TSH of 2.8 is within the normal range, but some patients are symptomatic at that level and would feel significantly better with thyroid support.

The standard reference ranges themselves are based on population averages, which include many unhealthy individuals. 'Normal' by these standards means you look like the average American. It doesn't mean you are optimally healthy. Functional medicine reframes the goal: not to identify disease, but to identify the trajectory toward disease early enough to correct it.

Thyroid: TSH is not enough

TSH (thyroid-stimulating hormone) is the standard thyroid screening test. It measures the pituitary's signal to the thyroid, not the thyroid hormones themselves. For a complete picture, Devorah recommends a full thyroid panel: TSH, Free T4, Free T3, Reverse T3 (rT3), and thyroid antibodies (anti-TPO and anti-thyroglobulin). Free T3 is the active thyroid hormone that drives metabolism, mood, body temperature, and energy. Many patients have normal TSH and T4 but low Free T3, particularly those on certain medications, under chronic stress, or with inflammatory conditions, and remain symptomatic on standard treatment as a result.

Reverse T3 indicates how much of your T4 is being converted to the inactive form rather than the active T3. Elevated rT3 is common in chronic stress and illness. Thyroid antibodies reveal autoimmune thyroid disease (Hashimoto's thyroiditis) years before TSH becomes abnormal, allowing earlier intervention.

Hormones: more nuanced than a single number

For women, a comprehensive hormone panel includes estradiol, progesterone, FSH, LH, DHEA-S, and free and total testosterone. These should ideally be timed to the appropriate phase of the menstrual cycle (day 3 for FSH/LH/estradiol; day 21–22 for progesterone in a 28-day cycle). For perimenopausal and menopausal women, understanding the hormonal landscape guides decisions about hormone replacement therapy and its risks and benefits. For men, a testosterone panel (total and free testosterone, SHBG, LH, FSH, estradiol, and prolactin) provides a complete picture of the hypothalamic-pituitary-gonadal axis.

Cortisol, the primary stress hormone, is underappreciated in routine labs. A morning serum cortisol and ideally a 4-point salivary cortisol test reveals how your adrenal glands are responding to chronic stress. Both high cortisol (common in acute stress) and low cortisol (common in adrenal fatigue patterns) have significant effects on energy, immune function, metabolism, and body composition.

Metabolic and cardiovascular risk markers

Fasting insulin, not just fasting glucose, reveals insulin resistance years before glucose becomes elevated. The HOMA-IR index (calculated from fasting glucose and fasting insulin) is a validated measure of insulin sensitivity. HbA1c provides a 3-month average of blood sugar levels and is more reliable than a single fasting glucose. Together, fasting insulin and HbA1c paint a much clearer picture of metabolic health than glucose alone.

For cardiovascular risk, an advanced lipid panel adds LDL particle number (LDL-P) and particle size: small dense LDL particles are far more atherogenic than large buoyant LDL even at the same total LDL-C. ApoB directly measures the number of atherogenic particles. Lp(a) is a genetically determined lipoprotein that significantly elevates cardiovascular risk and is completely missed by standard cholesterol panels. High-sensitivity CRP (hsCRP) measures systemic inflammation, the underlying driver of most cardiovascular events.

Nutrients: what most people are deficient in

Vitamin D (25-OH vitamin D) deficiency is prevalent, estimated to affect 40% of Americans, and associated with immune dysfunction, mood disorders, bone loss, metabolic dysfunction, and increased all-cause mortality risk. Optimal levels are generally 50–80 ng/mL, not simply 'above 30 ng/mL' (the conventional lower limit). Magnesium (RBC magnesium rather than serum, which is less sensitive) is deficient in the majority of Americans due to depleted soil and processed food diets. It's required for over 300 enzymatic reactions including ATP synthesis and glucose regulation.

Ferritin (iron storage protein) is a critical marker often omitted from standard labs. Low ferritin causes significant fatigue and cognitive impairment even when hemoglobin is normal. Elevated ferritin can indicate inflammation, liver disease, or hemochromatosis. B12 and folate should be measured, particularly in patients on metformin (which depletes B12), those following plant-based diets, or those with GI absorption issues. Zinc and selenium deficiencies are common and impair immune function, thyroid conversion, and antioxidant defense.

Key takeaways

Standard annual labs miss many early markers of dysfunction; 'normal' means average, not optimal
A full thyroid panel (TSH + Free T4 + Free T3 + rT3 + antibodies) reveals far more than TSH alone
Fasting insulin + HbA1c reveals insulin resistance years before glucose becomes elevated
Advanced lipid panels (LDL-P, ApoB, Lp(a)) add critical cardiovascular risk information
Vitamin D, magnesium, B12, ferritin, and zinc are commonly deficient and rarely tested
Devorah reviews all labs personally and provides context, not just a portal notification