Nutritional Deficiency Testing in Greenville, SC
Nutritional Deficiency Testing at IHP Greenville. Dr. Hendry, DAOM — functional medicine, root-cause diagnostics, personalized care. Call (864) 365-6156.
"I have been going to Dr. Hendry for 2 months now, for Acupuncture and Supplements. After 2 months, this is the best I have felt in over 2 years. My energy is so much better, my gut and digestion is back to normal."
— Danny Pyatt · March 2026 · Google Review
Serum magnesium is actively maintained within a narrow range by pulling magnesium out of cells and bone — which means serum magnesium can appear normal until the last 1% of body reserves are depleted. The patient with fatigue, muscle cramping, and insomnia who has "normal" magnesium on standard labs has not had the right test ordered. RBC magnesium reflects intracellular status accurately. I use the appropriate specimen type for each analyte — RBC for magnesium and zinc, methylmalonic acid for functional B12, omega-3 index for fatty acid status, 25-OH for vitamin D. The right test on the wrong specimen produces false reassurance that delays treatment by years.
How Nutritional Deficiency Testing Works
Dr. Hendry orders nutritional testing tailored to your presentation. Common markers include: vitamin D (25-OH), B12 (serum and methylmalonic acid for functional B12 status), folate, magnesium (RBC — more accurate than serum), zinc, selenium, iron studies (including ferritin for iron stores), CoQ10 (for mitochondrial and energy function), omega-3 index, and carnitine. Results are interpreted using optimal ranges, not just the absence of overt deficiency.
Conditions Treated with Nutritional Deficiency Testing
Micronutrient Testing Before Treatment vs. Empirical Supplementation Based on Symptoms
Nutritional supplementation is one of the most common forms of self-directed health management, yet the majority of supplement regimens are assembled based on symptom categories and marketing rather than measured biochemical need. The clinical consequences are two-fold: patients with genuine deficiencies receive inadequate doses of the wrong form, and patients without deficiencies accumulate excess of fat-soluble vitamins that create their own toxicity risks. A 50-year-old woman takes a daily multivitamin, generic B-complex, and vitamin D 1000 IU based on articles she has read. She reports persistent fatigue and low mood despite two years of supplementation. Testing reveals 25-OH vitamin D of 28 ng/mL, inadequate for T-regulatory cell function despite supplementation, because she requires a higher dose to overcome her absorption deficit. RBC magnesium is below the functional threshold. Omega-3 index is 3.8%, well below cardioprotective range. Her B12 is 290 pg/mL and methylmalonic acid is elevated, indicating functional B12 deficiency despite a normal serum B12, because she carries a variant impairing cellular uptake. Measured repletion at correct doses and forms, confirmed by follow-up testing at 90 days, produces objective biochemical improvement that symptom-guided supplementation spent two years failing to achieve.
Research & Evidence
Nutritional deficiencies are endemic in modern populations eating calorically adequate but micronutrient-depleted diets, and their clinical consequences include fatigue, immune dysfunction, mood disorder, cognitive impairment, and metabolic dysregulation, symptoms that are routinely attributed to other causes when nutritional testing is not performed. Aranow (J Investig Med. 2011) documented that vitamin D at levels below 30 ng/mL impairs T-regulatory cell differentiation, innate immune defensin production, and insulin receptor sensitivity, making deficiency a multi-system functional impairment rather than a bone health issue alone. Gartner et al. (J Clin Endocrinol Metab. 2002) demonstrated that selenium deficiency at levels within the lower portion of conventional reference ranges is sufficient to impair selenoenzyme deiodinase activity, reducing T4-to-T3 conversion and sustaining TPO antibody production in autoimmune thyroid disease. Bland (The Disease Delusion. 2014) documented that RBC magnesium, omega-3 index, and intracellular zinc reflect functional nutritional status far more accurately than serum measurements, and that deficiencies in these micronutrients independently drive insulin resistance, inflammatory cytokine production, and mitochondrial inefficiency. Our micronutrient protocol uses the appropriate specimen type for each analyte: RBC for magnesium and zinc, serum for 25-OH vitamin D and B12, whole blood for omega-3 index, and organic acid urine for functional B-vitamin status.
Your First Appointment
Bring all current supplements with dosages — Dr. Hendry evaluates whether your current supplementation is appropriate and adjusts based on test findings. A 10–12 hour fast is required for most nutritional panels.
Why Dr. Hendry for Nutritional Deficiency Testing
Dr. Hendry's research background and functional medicine training enable him to identify subclinical nutritional deficiencies that standard lab reference ranges fail to detect — and to prescribe specific, targeted supplementation based on test findings.