Biomarkers

Biomarkers are biological molecules found in blood, other body fluids, and body tissues. They provide indicators that are signs of normal health or of abnormal health conditions and disease.

Biomarkers are grouped in the Longevity Diagnostic Test Panels in relation to their function in the body. By looking at the individual test results and related tests, the risk or presence of cardiovascular disease, dementia, diabetes, and other major diseases can be assessed. Our risk assessments have the added benefit of putting your laboratory test results in the context of your health history.

Biomarkers Tested

The Longevity Standard Test Panel (Std) measures 27 biomarkers. The Longevity Advanced Test Panel (Adv) and the Longevity Advanced Plus Test Panel measure 37 biomarkers. The table below shows the biomarkers included in each test panel.

Biomarker Definitions and Reference Ranges

Alanine Aminotransaminase (ALT)

• Adult Males
• Normal 9-46 U/L
• High >46 U/L

• Adult Females
• Normal 6-29 U/L
• High >29 U/L

Serum alanine aminotransaminase (ALT) is a marker of liver function and liver disease. ALT values of 47-120 U/L in adult males and 30-120 U/L in adult females may indicate the presence of mild liver disease or fatty liver disease; a value >120 U/L indicates potentially significant liver disease. Common causes of liver disease include chronic alcohol intake, significant fat accumulation in the liver, gallstones, and certain medications. Liver disease can also result from some forms of cancer, various infections including hepatitis, autoimmune disease like primary biliary cirrhosis, and rare genetic disorders such as hemochromatosis. The treatment depends on the cause of the liver disease. (Back)

Albumin (Alb)

• Low <3.1 g/dL
• Normal 3.1-5.1 g/dL
• High >5.1 g/dL

Albumin is the major protein in your blood. Low serum levels may indicate liver disease, chronic illness, infections, malnutrition, or excess urinary excretion due to nephrotic syndrome. High serum levels may be due to dehydration and/or diarrhea. (Back)

Alkaline Phosphatase (AlkPhos)

• Adult Males
• Normal 35-144 U/L
• High >144 U/L

• Adult Females
• Normal 37-153 U/L
• High >153 U/L

Elevated serum alkaline phosphatase (AlkPhos) may be a marker of liver and/or bone disease. Serum levels may increase markedly during adolescence because of rapid bone growth. Elevated serum values may be due to significant obstructive liver disease, gallstones, a blockage of the bile duct, infections, pancreatic disease, bone disease including Paget’s disease, or various forms of cancer affecting the bone or liver. The treatment depends on the cause of the elevated level. (Back)

Aspartate Aminotransaminase (AST)

• Normal 10-35 U/L
• High >35 U/L

Serum aspartate aminotransaminase (AST) is a marker of liver function and liver disease. AST values of 35-120 U/L may indicate the presence of mild liver disease or fatty liver disease; a value >120 U/L indicates potentially significant liver disease. Common causes of liver disease include chronic alcohol intake, significant fat accumulation in the liver, gallstones, and certain medications. Liver disease can also result from some forms of cancer, various infections including hepatitis, autoimmune disease like primary biliary cirrhosis, and rare genetic disorders such as hemochromatosis. The treatment depends on the cause of the liver disease. (Back)

Bilirubin

• Normal 0.2-1.2 mg/dL
• High >1.2 mg/dL

Bilirubin is produced when red blood cells are broken down. It is excreted into the bile by the liver. A high blood bilirubin level may be due to liver disease, anemia, a drug reaction, or Gilbert’s disease (a benign inherited disorder).(Back)

Blood Urea Nitrogen (BUN)

• Normal ≤26 mg/dL
• High >26 mg/dL

Blood urea nitrogen is a measure of kidney function. A high value may indicate some degree of kidney dysfunction or dehydration. (Back)

Calcium

• Adult Males
• Low <8.6 mg/dL
• Normal 8.6-10.3 mg/dL
• High >10.3 mg/dL

• Adult Females
• Low <8.6 mg/dL
• Normal 8.6-10.4 mg/dL
• High >10.4 mg/dL

Serum calcium is a very important measure of kidney and parathyroid function. Low serum levels may be due to impaired function of the parathyroid glands, vitamin D deficiency, chronic kidney failure, and elevated serum phosphorus levels. High serum levels may be due to overactive parathyroid glands, various cancers (lung, breast, bone), excess vitamin D, some genetic conditions, long-term bedrest, dehydration, medications like lithium and thiazide diuretics, and excess calcium and vitamin D supplements. (Back)

Carbon Dioxide

• Low <20 mmol/L
• Normal 20-32 mmol/L
• High >32 mmol/L

Carbon dioxide is a measure of your lung and kidney function. Abnormal levels, both low and high, may be due to lung disease, kidney disease, adrenal disorders, and/or diabetes. (Back)

Chloride

• Low <98 mmol/L
• Normal 98-110 mmol/L
• High >110 mmol/L

Chloride is an important measure of the salt level in your blood. Low serum values may be due to overhydration, chronic lung disease, kidney disease, congestive heart failure, adrenal insufficiency, excessive vomiting, hyperaldosteronism, bromide intoxication, inappropriate antidiuretic hormone secretion, and excess extracellular fluid volume. High values may be due to dehydration, kidney disease, prolonged diarrhea, diabetes insipidus, adrenocortical hyperfunction, salicylate intoxication, or to the excessive intravenous infusion of saline or the extremely high dietary intake of salt. (Back)

Creatine Kinase (CK)

• Males
• Normal <196 U/L
• High >196 U/L

• Females
• Normal <143 U/L
• High >143 U/L

Creatine kinase (CK) is an enzyme found in muscle cells throughout the body. When there is muscle damage, muscle cells leak CK into the bloodstream. High serum CK levels may be due to various forms of muscle inflammation, muscle trauma, strenuous exercise, various genetic muscle diseases, hypothyroidism, and various medications including statins, fibrates, anti-viral medication, and angiotensin II receptor blockers. Markedly elevated levels (>1000 U/L) may indicate significant muscle damage and even severe muscle breakdown. (Back)

Creatinine

• Males
• Normal ≤1.35 mg/dL
• High <1.35 mg/dL

• Females
• Normal ≤1.05 mg/dL
• High >1.05 mg/dL

Creatinine is a more accurate measure of kidney function than blood urea nitrogen, which can be affected by dehydration. Creatinine levels can vary based on age and sex. A high value indicates some degree of kidney dysfunction. (Back)

Estimate Glomerular Filtration Rate (eGFR)

• Low ≤60 mL/min/1.73 m²
• High >60 mL/min/1.73 m²

Estimated glomerular filtration rate (eGFR), a calculated value based on your blood creatinine level and your sex, is a very accurate measure of kidney function. The kidneys have a critical role in removing waste products from the blood and in regulating blood volume and the levels of serum electrolytes like sodium, chloride, and potassium that are essential for life. According to the National Kidney Foundation, eGFR criteria for kidney function are as follows: normal >90 mL/min/1.73 m2; slightly decreased 60-89 mL/min/1.73 m2; moderately decreased 45-59 mL/min/1.73 m2; moderately to severely decreased 30-44 mL/min/1.73 m2; severely decreased 15-29 mL/min/1.73 m2; kidney failure <15 mL/min/1.73 m2. Individuals with eGFR levels <15 mL/min/1.73 m2 generally require dialysis and/or kidney transplantation. The major risk factors for kidney disease are high blood pressure and diabetes, both of which are also major risk factors for cardiovascular disease (CVD). Controlling these risk factors helps to prevent both kidney disease and CVD. A decreased eGFR is also a major CVD risk factor. (Back)

Folate

• Low <3.4 ng/mL
• Borderline 3.4-5.4 ng/mL
• High >5.4 ng/mL

Folate, also known as vitamin B9, is essential for normal neurological function and red blood cell metabolism. Low levels have been associated with anemia, elevated serum homocysteine levels, and an increased risk of cardiovascular disease and dementia. While the recommended daily allowance of folate is 0.4 mg/day, folate deficiency should be treated with 1.0-2.5 mg/day. Hypertensive individuals who were treated with folate 2.5 mg/day, vitamin B12 1 mg/day, and vitamin B6 50 mg/day had a 25% decrease in homocysteine blood levels and in the risk of stroke, compared to placebo. Significant alcohol intake is known to impair folate absorption. (Back)

Globulin

• Low <1.9 mg/dL
• Normal 1.9-3.7 mg/dL
• High >3.7 mg/dL

Globulin is a calculated measurement, determined by subtracting the concentration of albumin in the blood from the concentration of total protein. Globulin protein contains all the major immunoglobulin proteins that are important for the immune response. Low levels may be due to liver disease, chronic illness, and/or malnutrition. High values may be due to infection, inflammatory disease, immune disorders, and some cancers like multiple myeloma and lymphoma. (Back)

Glucose, Fasting

• Low <65 mg/dL
• Normal 65-99 mg/dL
• Prediabetic 100-124 mg/dL
• Diabetic ≥125 mg/dL

Glucose is the most important short-term energy source for the body. Your overnight fasting serum glucose value provides vital information about your diabetes status. According to the American Diabetes Association, diabetes is a leading cause of cardiovascular disease, kidney disease, neuropathy, and blindness. Diabetes can be prevented in prediabetic individuals with lifestyle modification (diet and physical activity) and weight loss if indicated. Metformin, pioglitazone, and semaglutide can be used to treat prediabetes and diabetes. These and other medications like sodium-glucose cotransporter 2 (SGLT2) inhibitors can be used to treat diabetes. Some individuals may require insulin therapy. We recommend that you consult with your healthcare provider if your fasting blood glucose value is low, prediabetic, or diabetic. (Back)

Hematocrit

• Males
• Low <38.5%
• Normal 38.5-50.0%
• High >50.0%

• Females
• Low <35.0%
• Normal 35.0-45.0%
• High >45.0%

Hematocrit measures the red blood cell count in the blood. Red blood cells are critical for carrying oxygen to the body tissues. A low level indicates the presence of anemia, which can be due to blood loss, to deficiency of iron, vitamin B12, or folate, or to chronic disease. A high level may indicate chronic lung disease, dehydration, heart failure, kidney or liver cancer, or polycythemia vera, a rare type of blood cancer. (Back)

Hemoglobin

• Males
• Low <13.2 g/dL
• Normal 13.2-17.1 g/dL
• High >17.1 g/dL

• Females
• Low <11.7 g/dL
• Normal 11.7-15.5 g/dL
• High >15.5 g/dL

Hemoglobin is a measure of the red blood cell count in the bloodstream. Red blood cells are critical for carrying oxygen to the body tissues. A low level indicates the presence of anemia, which can be due to blood loss, to deficiencies of iron, vitamin B12, or folate, or to chronic diseases including kidney disease, cancer, ulcerative colitis, or rheumatoid arthritis. A high level may indicate chronic lung disease, dehydration, heart failure, kidney or liver cancer, or polycythemia vera, a rare type of blood cancer. (Back)

High-Density Lipoprotein Cholesterol (HDL-C)

• Males
• Normal ≥40 mg/dL
• High CVD Risk <40 mg/dL

• Females
• Normal ≥50 mg/dL
• High CVD Risk <50 mg/dL

Serum high-density lipoprotein cholesterol (HDL-C), the “good” cholesterol, is the cholesterol carried on protective HDL particles. HDL-C levels can be increased by weight loss if indicated (an ideal body mass index is <25 kg/m2), smoking cessation if indicated, and sugar restriction. The control of fasting triglycerides in individuals with triglyceride blood levels ≥150 mg/dL and the control of fasting blood glucose in individuals with diabetes (fasting glucose ≥125 mg/dL) also increase serum HDL-C levels. (Back)

High sensitivity C-reactive protein (hs-CRP)

• Optimal <1.0 mg/L
• Borderline 1.0-3.0 mg/L
• High CVD Risk >3.0-10.0 mg/L
• Very High CVD Risk >10.0 mg/L

C-reactive protein (CRP) is a measure of the level of inflammation and/or infection in the body. CRP is measured with a high sensitivity assay in order to increase the accuracy of the measurement; the test is, therefore, designated as hs-CRP. CRP values >10.0 mg/L are usually associated with infection or marked inflammatory or auto-immune disease like rheumatoid arthritis. Values >3.0 mg/L are associated with increased cardiovascular disease (CVD) risk. CRP levels can be lowered in the moderate range with weight loss, if indicated, and by statin therapy. Reducing CRP levels to <1.0 mg/L (optimal) and LDL-C levels to <70 mg/dL (optimal) with rosuvastatin 20 mg/day therapy has been shown to lower CVD risk by about 80%, compared to placebo, in individuals with hs-CRP levels >2.0 mg/L. Omega-3 fatty acids and colchicine (0.5 mg/day) have also been shown to lower CRP and CVD risk. (Back)

Homocysteine

• Males
• Normal <11.4 µmol/L
• High ≥11.4 µmol/L

• Females
• Normal <10.4 µmol/L
• High ≥10.4 µmol/L

Homocysteine is an amino acid that is converted to methionine (an essential amino acid) and cysteine (an amino acid important for reducing inflammation) by the action of B vitamins, specifically folate, vitamin B6, and vitamin B12. High serum values >14 µmol/L have been associated with an increased risk of cardiovascular disease and dementia. An international consensus conference has recommended that serum homocysteine levels be optimized to <10 µmol/L with vitamin B supplementation (folate at least 0.8 mg/day; vitamin B12 at least 0.5 mg/day; vitamin B6 at least 20 mg/day) to decrease the risk of all-cause dementia, especially in individuals >60 years of age. (Back)

Lipoprotein(a) (Lp(a))

• Optimal <75 nmol/L
• Moderate CVD Risk 75-125 nmol/L
• High CVD Risk >125 nmol/L

Serum lipoprotein(a) or Lp(a) is a lipoprotein particle circulating in the bloodstream that is similar to the low-density lipoprotein (LDL) particle, except that it has another protein, known as apo(a), attached to it. Lp(a) levels are genetically determined. A high level (>125 nmol/L) has been associated with increased cardiovascular disease (CVD) risk. Patients with elevated levels benefit significantly from low dose aspirin therapy. The treatment for elevated Lp(a) also involves optimizing all other risk factors including blood pressure and blood glucose and LDL-C levels. In individuals with established CVD, the use of a PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor like evolocumab or alirocumab is recommended; this therapy lowers Lp(a) by 25-30% and optimizes LDL-C levels. (Back)

Low-density Lipoprotein Cholesterol (LDL-C)

• Normal <100 mg/dL
• High CVD risk ≥100 mg/dL

Serum low-density lipoprotein cholesterol (LDL-C), frequently called “bad” cholesterol, is the cholesterol carried on atherogenic LDL, the major cholesterol-carrying lipoprotein particle. A high LDL-C blood level is a major cardiovascular disease (CVD) risk factor, especially if it is ≥160 mg/dL. You should aim for a normal value of <100 mg/dL and an optimal value of <70 mg/dL, especially if you have established CVD (post-heart attack, bypass, angioplasty, or a cardiac calcium score >100) or are at high 10-year risk for CVD (≥7.5%). LDL-C can be optimized with nutritional modification, by restricting meat, dairy fat, and sugar and increasing the intake of fruits, vegetables, and grains. In high-risk individuals or individuals with established CVD, statin therapy (rosuvastatin 5-40 mg/day) and, if necessary, ezetimibe (10 mg/day) or a PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor like evolocumab or alirocumab may be needed to decrease LDL-C to <70 mg/dL. Rosuvastatin (5-40 mg/day) should be taken along with co-enzyme Q10 200 mg/day to prevent statin-induced muscle problems. (Back)

Mean Cell Volume (MCV)

• Low <80 fL
• Normal 80-100 fL
• High >100 fL

Mean cell volume (MCV) measures the mean red cell volume in the bloodstream. If you are anemic, a low MCV may indicate iron deficiency or chronic blood loss or a variety of hemoglobin disorders. A normal MCV may indicate acute blood loss or the anemia of chronic disease. An elevated MCV may indicate a deficiency of vitamin B12 or folate, liver disease, or a myeloproliferative disorder. Other measures of red blood cell normality include mean cell hemoglobin (MCH); mean cell hemoglobin concentration (MCHC), and red cell distribution width (RDW). These tests are all useful in the diagnosis of anemia and complement MCV. (Back)

Mean Platelet Volume (MPV)

• Low <7.5 fL
• Normal 7.5-12.5 fL
• High >12.5 fL

Mean platelet volume (MPV) is a measure of platelet size. A high MPV value with a low platelet count may indicate increased platelet consumption or turnover seen with an enlarged spleen. A low value has been linked to inflammatory bowel disease, chemotherapy, and certain types of anemia. (Back)

Non-HDL cholesterol (non-HDL-C)

• Normal <130 mg/dL
• High CVD risk ≥130 mg/dL

Non-HDL-C is calculated by subtracting HDL-C from total cholesterol. It represents the sum of the cholesterol in all lipoprotein particles causing cardiovascular disease (CVD). You should aim for a normal value of <130 mg/dL or for an optimal value of <100 mg/dL if you have established CVD or are at high risk for developing CVD (10-year CVD risk ≥7.5%). Your non-HDL-C blood levels can be optimized in the same way as LDL-C blood levels, by restricting the intake of meat, dairy fat, and sugar and increasing the intake of fruits, vegetables, and grains. In high-risk individuals or individuals with established CVD, statin therapy (rosuvastatin 5-40 mg/day) and, if necessary, ezetimibe (10 mg/day) or a PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor like evolocumab or alirocumab may be needed to decrease non-HDL-C levels to <100 mg/dL. Rosuvastatin (5-40 mg/day) should be taken along with co-enzyme Q10 200 mg/day to prevent statin-induced muscle problems. (Back)

Omega 3 Fatty Acids

• Low ≤3.7%
• Borderline 3.8-5.4%
• Optimal ≥5.5%

Omega-3 fatty acids include eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). The Onega-3 Check Test measures the sum of these three fatty acids as a percentage of the concentration of total fatty acids in the blood. Omega 3 fatty acids are important for maintaining the fluidity and function of cell membranes, especially in the brain and the heart. A low blood Omega-3 Fatty Acid Index value has been associated with an increased risk of cardiovascular disease and dementia. Optimal values can be achieved with increased consumption of oily fish in the diet or supplementation with two (2) or more 1 gram omega-3 fish oil capsules per day, and for brain health two (2) 200 mg capsules of oral DHA per day. (Back)

Platelet Count

• Low <140 Thousand/µL
• Normal 140-400 Thousand/µL
• High >400 Thousand/µL

Platelets, along with clotting factors, are important for blood clotting. A low platelet count can be due to a variety of causes including an enlarged spleen, viral infections including hepatitis or human immunodeficiency virus (HIV), heavy alcohol consumption, various cancers including leukemia, some types of anemia, chemotherapy drugs, and radiation therapy. An elevated platelet count can be due to infections, iron deficiency, cancer, certain types of anemia, and inflammatory disorders including rheumatoid arthritis, sarcoidosis, and/or inflammatory bowel disease. (Back)

Potassium

• Low <3.5 mmol/L
• Normal 3.5-5.3 mmol/L
• High >5.3 mmol/L

Potassium is a very important measure of body health status. Low serum potassium values may be due to excessive alcohol intake, kidney disease, uncontrolled diabetes, diarrhea, diuretic use, excessive laxative use, excessive sweating, folic acid deficiency, primary aldosteronism, certain antibiotics, and vomiting. High serum values may be due to kidney disease, adrenal insufficiency, certain antihypertensive medications (angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, beta blockers), dehydration, excess potassium supplementation, and uncontrolled diabetes. Occasionally high levels may be due to improper blood collection with excess red cell breakdown (hemolysis). A hemolyzed specimen is usually noted by the laboratory receiving it, and the potassium test may not be performed. (Back)

Sodium

• Low <135 mmol/L
• Normal 135-146 mmol/L
• High >146 mmol/L

Sodium is a very important measure of the salt level in your blood. Low values may be due to the use of certain medications (like diuretics and antidepressants), heart, kidney, and liver problems, inappropriate anti-diuretic hormone syndrome, excess fluid intake, amphetamine use, and adrenal insufficiency. High levels may be due to Cushing syndrome, diabetes insipidus, hyperaldosteronism, and significant fluid loss from excessive sweating, diarrhea, or burns. Too much salt or sodium bicarbonate in the diet and certain medicines, including corticosteroids, laxatives, lithium, ibuprofen, and naproxen, can elevate sodium levels. (Back)

Thyroid stimulating hormone (TSH)

• Low <0.4 mIU/L
• Normal 0.4.4.5 mIU/L
• High >4.5 mIU/L

Thyroid stimulating hormone (TSH), which is produced in the pituitary gland, is a precise measure of thyroid function. A high value indicates the presence of an underactive thyroid gland (hypothyroidism), while a low value indicates the presence of an overactive thyroid gland (hyperthyroidism). Follow-up testing is recommended for individuals with either of these abnormalities in order to assess serum levels of the thyroid hormones, specifically total and free T3 and total and free T4, and to ascertain actual thyroid function. Individuals who have a high TSH level and low thyroid hormone levels due to hypothyroidism may require thyroid hormone replacement therapy. Hypothyroidism is very common in the elderly (>10% of the female population; >5% of the male population) and predisposes to elevated LDL-C blood levels. (Back)

Total Cholesterol

• Normal <200 mg/dL
• High ≥200 mg/dL

Serum total cholesterol is the sum of the cholesterol concentration in all the cholesterol-carrying lipoproteins in your blood. It is important to know not only this value but also how your blood cholesterol is being carried on low-density lipoproteins (LDL) and high-density lipoproteins (HDL). (Back)

Total Protein

• Low <6.1 mg/dL
• Normal 6.1-8.1 mg/dL
• High >8.1 mg/dL

Total protein is a measure of the total protein level in your blood. A low serum level may be due to liver disease, chronic illness, malnutrition, decreased protein production, or increased protein loss due to kidney or intestinal disease. High serum levels may be due to infections, amyloidosis, dehydration, hepatitis, HIV/AIDS, monoclonal gammopathy, and/or multiple myeloma. (Back)

Triglycerides (TG)

• Normal <150 mg/dL
• High ≥150-500 mg/dL
• Very High >500 mg/dL

Triglyceride (TG), like cholesterol, is a major fat in the bloodstream. A high value is associated with increased cardiovascular disease risk; a very high value >500 mg/dL, with fatty liver disease and pancreatitis. TG levels can be decreased with weight loss if indicated, restriction of sugars, and control of fasting blood glucose to <125 mg/dL in individuals with diabetes. For people with very high values, despite lifestyle modification, treatment with micronized fenofibrate 200 mg/day and/or omega-3 fatty acids 4-6 one-gram capsules/day will lower TG values significantly. Statin therapy also lowers TG levels. (Back)

Uric Acid

• Males
• Normal 4.0-8.0 mg/dL
• High >8.0 mg/dL

• Females
• Normal 2.5-7.0 mg/dL
• High >7.0 mg/dL

An elevated serum uric acid level has been associated with an increased risk of cardiovascular disease and gout. Not all individuals with high uric acid values will develop gout, and some individuals will develop gout at somewhat lower levels. Individuals with gout can have painful joints, especially in their feet and big toe, and are at increased risk for kidney stones. Individuals with elevated serum uric acid levels should limit their intake of alcoholic beverages and drinks sweetened with fruit sugar (fructose); they should minimize the intake of red meat, especially organ meats like liver. Individuals who have both an elevated uric acid level and attacks of gout are candidates for allopurinol treatment (200-300 mg/day) to lower the blood uric acid level to <6.0 mg/dL and minimize the risk of attacks of gouty arthritis and kidney stones. (Back)

Vitamin B12

• Low <200 pg/mL
• Normal 200-1100 pg/mL
• Optimal %gt;700 pg/mL

Vitamin B12 is necessary for normal neurological function and red blood cell metabolism. Low levels have been associated with anemia, elevated serum homocysteine levels, and increased risk for cardiovascular disease and dementia. The recommended daily allowance of vitamin B12 is 2.4 mcg/day. Vitamin B12 deficiency, however, should be treated with 1000 mcg/day (that is, 1 mg/day) to optimize blood levels. Treatment of hypertensive patients with vitamin B12 1 mg/day plus folate 2.5 mg/day and vitamin B6 50 mg/day lowered homocysteine levels and the risk of stroke by 25%, compared to placebo. (Back)

Vitamin D

• Low <30 ng/mL
• Optimal 30-100 ng/mL
• High %gt;100 ng/mL

Vitamin D plays an important role in bone and cardiovascular health. A daily intake of 600 international units (IU)/day for all adults up to 70 years of age and 800 IU/day for those older than 70 years of age is recommended. Individuals with low levels of vitamin D (<30 ng/mL) should be supplemented with 2,000 IU of vitamin D per day until blood vitamin D levels are in the 30-100 ng/mL range, which is optimal for bone and cardiovascular health, and then supplemented with 800 IU/day to maintain optimal levels. (Back)

White Blood Cell Count (WBC)

• Low <3.8 Thousand/µLL
• Normal 3.8-10.8 Thousand/µL
• High >10.8 Thousand/µL

White blood cell count is a measure of the level of white blood cells in your bloodstream. White blood cells are very important for combating infection or inflammation. Low levels may be due to chemotherapy, radiation, bone marrow failure, leukemia, lupus erythematosus, rheumatoid arthritis, malnutrition, and certain medications including some antibiotics. High levels may be due to infections, inflammatory or allergic disorders, abnormalities in the bone marrow including leukemia, smoking, and chronic lung disease. (Back)