HealthieOne Complete measures 250+ biomarkers across 15 health categories. Because this panel is far more comprehensive than a standard blood test, a few simple preparation steps will help ensure the most accurate results possible. 

  1. Stop all non-essential supplements at least 4 days before testing to reveal your true baseline levels.
  2. Fast for 10 to 12 hours (water only) for accurate glucose, lipid, and bile acid results.
  3. Avoid fish, seafood, red meat, caffeine, and alcohol for 24 hours 
  4. Skip intense exercise for 24 to 48 hours before your draw.
  5. Schedule a morning blood draw (before 10 AM)
  6. Sit for 15 minutes before the draw
  7. Stay normally hydrated: at least 2 cups or 1 bottle of 16 oz of plain water.
  8. Note your menstrual cycle day if applicable.
  9. Report all medications to your HealthieOne portal but never stop prescribed medications without medical guidance.

See detailed explaination below:

1. Vitamins and Supplements (Stop 4 Days Before)

You have two options:

  • If you continue your current supplement regimen without interruption, the results will reflect your vitamin/supplement intake.
  • If you discontinue them for at least 4 days prior to testing, the results will reflect your true baseline without these interventions.

We recommend the latter approach to determine your authentic baseline levels. This applies to all vitamin, mineral, amino acid, omega-3/fish oil, and herbal supplements.

Essential Supplements to Consider NOT Stopping

  • Prescription vitamins or minerals
  • Supplements for diagnosed deficiencies
  • Heart medications containing nutrients
  • Supplements preventing serious deficiency diseases

Always consult your prescribing provider before stopping any prescribed supplement or medication. 
Learn more about How Vitamins and Supplements Could Alter Your Blood Test Results

2. Fasting (10 to 12 Hours, Water Only)

Cleveland Clinic recommends that "in most cases, you need to fast for 10 to 12 hours before your lipid panel blood test. Fasting means not eating or drinking anything except water." MedlinePlus (National Library of Medicine) confirms that "you should also not: chew gum, smoke, and exercise."

3. Fish and Seafood (Avoid 24 Hours Before)

Cleveland HeartLab specifies that "patients should fast overnight and refrain from consuming fish or other seafood the day before the blood draw to avoid false elevations in TMAO." Quest Diagnostics provides the same guidance, advising patients to "fast overnight and refrain from consuming fish, other seafood, or fish oil supplements the day before the blood draw." European Journal of Nutrition further supports this 24 hour window, finding that circulating TMAO levels return to baseline within 24 hours of consuming high TMAO content seafood.

Fish and shellfish are also major dietary sources of taurine, anserine, carnosine, and methylhistidines (1-Methylhistidine, 3-Methylhistidine), as well as omega-3 fatty acids (DHA, EPA, DPA). Avoiding seafood for 24 hours helps ensure these markers reflect your chronic status rather than a single recent meal.

4. Red Meat and Organ Meats (Avoid 24 Hours Before)

MedlinePlus (National Library of Medicine) advises that "you may be told to not eat meat for 24 hours before your test" because "meat can temporarily increase creatinine levels." Cleveland Clinic identifies "red meat and organ meats" among the high-purine foods that raise uric acid levels. Nature Medicine demonstrated that intestinal microbiota metabolism of L-carnitine, a nutrient abundant in red meat, promotes TMAO production. A large red meat meal can also acutely elevate carnitine, 3-methylhistidine, and creatinine.

 5. Caffeine (Avoid 12 to 24 Hours Before)

Psychosomatic Medicine found that "caffeine challenge doses caused a robust increase in cortisol across the test day". Pharmacology Biochemistry and Behavior confirmed that "Cortisol release in response to stress and caffeine therefore appears to be a function of the type of stressor and the sex of the subject". Avoid coffee, tea, energy drinks, and caffeinated sodas for 24 hours before your blood draw.

6. Alcohol (Avoid 24 to 48 Hours Before)

Cleveland Clinic notes that "alcohol and certain medications can also cause high levels of GGT." Cleveland Clinic also lists "alcohol use" among the causes of elevated liver enzymes (ALT, AST). MedlinePlus (National Library of Medicine) advises that for certain tests "you may be asked not to drink alcohol for a longer period of time." Avoid all alcoholic beverages for at least 24 to 48 hours before testing.

7. Histamine-Rich Foods (Avoid 24 Hours Before)

HealthieOne measures blood histamine levels. Cleveland Clinic notes that "histamines are naturally occurring chemicals in foods like cheese, pineapples, bananas, avocados and chocolate. Red wine and some white wines also have histamines." Aged cheeses, fermented foods (kimchi, sauerkraut, miso), cured meats, and vinegar are also high in exogenous histamine and can cause false elevations. Avoid these foods for 24 hours before your blood draw.

8. Cruciferous Vegetables and Smoking (Awareness)

Cleveland Clinic explains that "eating a lot of raw cruciferous vegetables can reduce your uptake of iodine" and can affect thyroid function. The Mayo Clinic confirms that "eating a lot of these vegetables could limit your thyroid's uptake of iodine." Cruciferous vegetables (broccoli, cauliflower, cabbage, kale, Brussels sprouts) contain glucosinolates that metabolize to thiocyanate. Cigarette smoke is also a major source. Your thiocyanate level will reflect both dietary cruciferous vegetable intake and tobacco exposure. 

9. Intense Exercise (Avoid 24 to 48 Hours Before)

Cleveland Clinic notes that "intense exercise can increase CK levels" as the enzyme leaks from damaged muscle cells into the bloodstream. MedlinePlus confirms that muscle injuries "including injuries from accidents, serious burns, or extreme exercise" elevate creatine kinase. Biron Groupe Santé further explains that exercise increases levels of "urea, creatinine, creatine kinase, lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alkaline phosphatase, bilirubin, uric acid, as well as the white blood cell count." 

10. Morning Draw (Before 10 AM Preferred)

UCSF Health states: "Your health care provider will likely have you do the test early in the morning. This is important because cortisol level varies throughout the day." Cleveland Clinic confirms that "the level of cortisol in your blood, pee and spit is usually highest in the early morning and declines throughout the day." Cortisol, DHEA, testosterone, and iron all peak in the early morning and decline throughout the day. For the most consistent and clinically interpretable results, schedule your blood draw before 10 AM.

11. Hydration (at least 2 cups or 1 bottle of 16 oz of plain water)

Drink normal amounts of water before your blood draw. MedlinePlus also confirms that "abnormal levels of red blood cells, hemoglobin, or hematocrit may be a sign of dehydration." MedlinePlus adds that high albumin levels "may be a sign of dehydration." Overhydration can dilute these values. Simply drink water as you normally would.

12. Sit for 15 Minutes Before the Draw

StatPearls (NCBI Bookshelf) states in its Phlebotomy chapter that "the patients who are planned to undergo the procedure in an office-based setting should be advised to stay in a sitting position for at least 15 minutes before initiating the procedure" and that "statistically significant differences with changing patients' positioning due to several biochemistry parameters have been reported." Revista Brasileira de Hematologia e Hemoterapia confirmed that changing from supine to standing "caused clinically significant increases in the hemoglobin, hematocrit, red blood cell, leukocyte, neutrophil, lymphocyte, basophil and platelet counts, and mean platelet volume". Clinica Chimica Acta found that plasma volume decreased by 9.7% when patients moved from sitting to standing, with meaningful increases in albumin, total protein, calcium, total and HDL cholesterol, triglycerides, and multiple liver enzymes. Sit quietly for at least 15 minutes before your phlebotomist draws your blood.

13. Note Your Menstrual Cycle Day (Women)

Labcorp OnDemand recommends that for estradiol testing, "it is recommended to test on day 3 of your menstrual cycle (cycle day 1 is the first day of your period). If you have no menstrual cycle or have irregular menstrual cycles, you can test at any time." because "day 3 of your menstrual cycle is considered the 'baseline' because that's typically when estradiol levels are most stable." UCSF Health notes that "Blood progesterone levels start to rise midway through the menstrual cycle. It continues to rise for about 6 to 10 days, and then falls if the egg is not fertilized". MedlinePlus (National Library of Medicine) confirms that for a progesterone test, "you may need to know the first day of your last menstrual period" and that results depend on "where you were in your menstrual cycle when your blood sample was taken." When scheduling your blood draw, note your cycle day so your HealthieOne can interpret your hormone results in the proper context.

14. Medications (Report All, Do Not Stop Without Medical Guidance)

Certain medications can affect specific biomarkers. Always report all current medications to your HealthieOne portal. Do not stop any prescribed medication without consulting your prescribing provider.

MedlinePlus (National Library of Medicine) advises "telling their provider about any medicines, vitamins, or supplements that you are taking" and emphasizes: "But don't stop taking any medicines unless your provider tells you to." MedlinePlus also recommends: "Ask your provider whether it's okay to take your usual prescription medicines and/or over-the-counter medicines" and "Let your provider know about any vitamins and supplements that you take, too."

Notable medication effects on HealthieOne markers include:

  • Corticosteroids (prednisone, hydrocortisone, dexamethasone): Elevate Cortisol and Cortisone. Suppress DHEA and DHEA-S.
  • Thyroid medications (levothyroxine, liothyronine): Directly alter T4 and T3 levels.
  • Hormone replacement therapy and oral contraceptives: Alter Estradiol, Estrone, Progesterone, Testosterone, DHEA-S, Cortisol.
  • Levodopa/carbidopa: Elevate DOPA and 3-O-Methyldopa.
  • Allopurinol/febuxostat: Lower Uric acid and Xanthine.
  • Statins: May modestly lower CRP.
  • Metformin: May affect Glucose, Lactic acid, and impair B12 absorption (raising Methylmalonic acid). Cleveland Clinic notes that "certain medications can cause low levels of vitamin B12 in your body, including metformin, proton pump inhibitors, H2 blockers and oral birth control pills." Mayo Clinic confirms that "taking this diabetes medicine might lower the body's ability to absorb vitamin B-12."
  • PPIs (omeprazole, pantoprazole): Can impair B12 absorption and reduce Iron and Magnesium absorption. Mayo Clinic notes that "taking omeprazole (Prilosec), lansoprazole (Prevacid) or other stomach acid-reducing medicine might lower the body's ability to absorb vitamin B-12."
  • Antibiotics (recent course within 2 to 4 weeks): Will significantly lower TMAO, Indole-3-propionate, Indole-3-acetic acid, Hippuric acid, and other gut microbiome-derived metabolites.