Evidence-Based Supplement & Herb Guides

Latex IgE Test: Latex Allergy, Positive Result, Cross-Reactivity, and Meaning

$Learn what a latex IgE test measures, how to interpret positive or negative results, when component testing helps, and how latex–fruit cross-reactivity affects diagnosis.$

A latex IgE test is a blood test that looks for immunoglobulin E antibodies directed against proteins in natural rubber latex. It can support...

Leukotriene E4 Urine Test: Mast Cell Activation, Allergy, and Inflammation Meaning

Learn what a leukotriene E4 urine test measures, how timing and collection affect results, what elevated LTE4 may mean, and how it fits mast cell and asthma evaluation.

A leukotriene E4 urine test measures the stable end product of cysteinyl leukotriene production. These inflammatory chemicals are released by mast cells, eosinophils, basophils,...

Mast Cell Activation Test Panel: Tryptase, Histamine, Prostaglandins, and Leukotrienes

Understand what a mast cell activation test panel includes, how tryptase and urine mediators are timed, what result patterns mean, and how MCAS differs from mastocytosis and allergy.

A mast cell activation test panel uses blood and urine markers to look for objective evidence that mast cells released inflammatory mediators during a...

Milk Component IgE Test: Casein, Whey Proteins, Allergy Risk, and Meaning

Learn how casein, alpha-lactalbumin, and beta-lactoglobulin IgE results relate to cow’s milk allergy, baked-milk tolerance, oral food challenges, and follow-up testing.

A milk component IgE test measures antibodies to individual cow’s milk proteins rather than testing only a whole-milk extract. The main components include caseins,...

N-Methylhistamine Urine Test: Mast Cell Activation, Histamine Metabolite, and Meaning

Learn how an N-methylhistamine urine test reflects histamine metabolism, how random and 24-hour collections differ, what high results may mean, and how the test fits mast cell evaluation.

An N-methylhistamine urine test measures the main urinary metabolite produced when the body breaks down histamine. Because histamine itself disappears quickly from blood, its...

Nut Allergy IgE Panel: Peanut, Tree Nuts, Component Testing, and Allergy Risk

Learn how peanut and tree nut IgE panels are interpreted, which components improve specificity, how cross-reactivity differs from co-allergy, and when oral food challenges can clarify risk.

A nut allergy IgE panel measures antibodies to peanut and selected tree nuts, such as cashew, pistachio, walnut, pecan, hazelnut, almond, Brazil nut, and...

Peanut Component IgE Test: Ara h Proteins, Anaphylaxis Risk, and Peanut Allergy Meaning

Learn how Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 8, and Ara h 9 results affect peanut allergy diagnosis, challenge decisions, and anaphylaxis risk assessment.

A peanut component IgE test measures antibodies to individual peanut proteins, known as Ara h components. It can distinguish sensitization to stable seed-storage proteins,...

Plasma Histamine Test: Mast Cell Activation, High Levels, Timing, and Meaning

Understand plasma histamine testing, including the short collection window, strict sample handling, causes of high results, and its role in anaphylaxis and mast cell activation evaluation.

A plasma histamine test measures histamine circulating in the liquid portion of blood. Histamine rises quickly when mast cells or basophils release their stored...

Prostaglandin D2 Test: Mast Cell Activation, High Levels, and Meaning

Learn what a prostaglandin D2 urine metabolite test measures, how random and 24-hour collections differ, and what high, normal, or medication-affected results may mean.

A prostaglandin D2 test looks for evidence that the body is producing excess prostaglandin D2, a short-lived lipid mediator released in large amounts by...

Respiratory Allergy Panel: Inhalant Allergens, Specific IgE, Asthma, and Rhinitis

Learn how a respiratory allergy panel tests specific IgE to pollen, mites, pets, molds, and other inhalants, and how results relate to rhinitis, asthma, cross-reactivity, and treatment.

A respiratory allergy panel measures specific IgE antibodies to selected airborne allergens, such as pollens, dust mites, animal dander, molds, and cockroach. The test...

Shellfish Allergy IgE Test: Shrimp, Crab, Lobster, Tropomyosin, and Allergy Risk

Understand shrimp, crab, lobster, and tropomyosin IgE testing, including cross-reactivity with mites, component results, oral challenges, and what positive or negative values mean.

A shellfish allergy IgE test measures antibodies to shrimp, crab, lobster, or other shellfish proteins. It can support an IgE-mediated allergy diagnosis when the...

Specific IgE Blood Test: Allergy Triggers, Positive Result, and Clinical Meaning

Learn how specific IgE blood tests identify allergen sensitization, what positive and negative values mean, when component testing helps, and how results guide allergy diagnosis.

A specific IgE blood test measures antibodies directed at one allergen, such as peanut, cat dander, dust mite, grass pollen, latex, or insect venom....

Total IgE Blood Test: High Levels, Allergy, Asthma, Parasites, and Immune Meaning

Learn what total IgE measures, why levels rise with allergy, eczema, asthma, parasites, or immune disorders, and how normal, high, and very high results are evaluated.

A total IgE blood test measures the combined amount of immunoglobulin E in serum, regardless of which allergens or antigens it recognizes. A high...

Tryptase Blood Test: High Levels, Mast Cell Activation, Anaphylaxis, and Mastocytosis

Learn how acute and baseline tryptase tests are timed and compared, what high results can mean, and how tryptase supports evaluation of anaphylaxis, MCAS, hereditary alpha-tryptasemia, and mastocytosis.

A tryptase blood test measures a protein released mainly by mast cells. The result can answer two different questions, depending on when the sample...

Wheat Component IgE Test: Wheat Allergy, Omega-5 Gliadin, and Exercise-Related Risk

Learn how wheat component IgE testing interprets omega-5 gliadin, Tri a 14, glutenins, cross-reactivity, and exercise-related anaphylaxis risk, and what positive or negative results can mean.

A wheat component IgE test looks for antibodies to individual wheat proteins rather than measuring only IgE to a whole-wheat extract. It is most...

Calcitonin Blood Test: High Levels, Medullary Thyroid Cancer, C-Cells, and Results

Learn how the calcitonin blood test measures thyroid C-cell activity, why levels rise, how results relate to medullary thyroid cancer, and what follow-up may involve.

A calcitonin blood test measures a hormone made mainly by the thyroid gland’s parafollicular cells, better known as C-cells. The test is most useful...

Free T3 (Free Triiodothyronine) Test: High, Low, Normal Range, and Thyroid Results

Understand what a free T3 blood test measures, why levels may be high or low, how normal ranges vary, and when results help diagnose thyroid disease.

A free T3 test measures the small portion of triiodothyronine circulating without a binding protein. T3 is the thyroid hormone that acts most strongly...

Free T4 (Free Thyroxine) Test: High, Low, Normal Range, and Thyroid Results

Learn how a free T4 blood test helps identify hypothyroidism, hyperthyroidism, and pituitary disease, why ranges vary, and what high or low results may mean.

A free T4 blood test measures the unbound portion of thyroxine, the main hormone released by the thyroid gland. It is commonly paired with...

Free Thyroxine Index (FTI) Test: Thyroid Function, T4 Binding, and Results

Learn how the free thyroxine index combines total T4 and T3 uptake, what high or low FTI results suggest, and when binding proteins can affect interpretation.

The free thyroxine index, usually shortened to FTI or FT4I, is a calculated estimate of biologically available thyroxine. It combines a total T4 result...

Graves Disease Blood Test Panel: TSH, Free T4, T3, TRAb, TSI, and Results

Understand the Graves disease blood test panel, including TSH, free T4, T3, TRAb, and TSI patterns used for diagnosis, treatment monitoring, and pregnancy care.

A Graves disease blood test panel usually combines thyroid function tests with antibodies that target the TSH receptor. The typical untreated pattern is a...