Evidence-Based Supplement & Herb Guides

Complement Factor H Test: Complement Regulation, Kidney Disease, and Meaning

Learn what Complement Factor H testing measures, why normal levels can miss dysfunction, and how antigen, autoantibodies, genetics, C3 patterns, kidney biopsy, and TMA evaluation fit together.

A complement Factor H test evaluates one of the alternative pathway’s most important protective regulators. Factor H circulates in blood, recognizes C3b, accelerates breakdown...

Diphtheria Antibody Test: Vaccine Immunity, Protection Level, and Immune Response

Learn how to interpret a diphtheria antibody test, including 0.01 and 0.1 IU/mL thresholds, timed vaccine-response testing, immune deficiency clues, confounders, and active-disease limits.

A diphtheria antibody test measures IgG directed against diphtheria toxoid, the inactivated toxin used in DTaP, Tdap, and Td vaccines. It is most useful...

Free Light Chain Test: Kappa, Lambda, Ratio, and Plasma Cell Disorders

Understand serum free light chains, including kappa, lambda, the ratio, kidney effects, MGUS and myeloma patterns, the ratio-of-100 rule, companion tests, and urgent warning signs.

A serum free light chain test reports three linked results: free kappa, free lambda, and the kappa-to-lambda ratio. Plasma cells normally make complete immunoglobulins...

IgA Blood Test: High, Low, Normal Range, Mucosal Immunity, and Celiac Disease

Understand IgA blood test ranges, causes of high or low IgA, mucosal immune function, selective IgA deficiency, and how IgA affects celiac testing.

An IgA blood test measures immunoglobulin A, an antibody that helps protect the body’s moist surfaces, including the airways, digestive tract, eyes, and mouth....

IgE Blood Test: High, Low, Allergy, Asthma, Parasites, and Meaning

Learn how total and specific IgE blood tests are interpreted, why IgE may be high or low, and how results relate to allergy, asthma, parasites, and immune disorders.

An IgE blood test measures immunoglobulin E, the antibody class most closely linked with immediate allergic reactions and defense against certain parasites. Doctors may...

IgG Blood Test: High, Low, Normal Range, Immune Function, and Infection Risk

Understand IgG blood test ranges, causes of high and low IgG, infection risk, immune function, subclass testing, and the follow-up used for abnormal results.

An IgG blood test measures immunoglobulin G, the most abundant antibody in the bloodstream and a major source of long-term protection after infection or...

IgG Subclass Test: IgG1, IgG2, IgG3, IgG4, Infections, and Immune Deficiency

Learn how IgG1, IgG2, IgG3, and IgG4 tests are interpreted, why subclass levels may be low or high, and how infection history and vaccine responses confirm immune deficiency.

An IgG subclass test separates total immunoglobulin G into IgG1, IgG2, IgG3, and IgG4. These four antibody groups differ in abundance, the antigens they...

IgG4 Blood Test: High Levels, IgG4-Related Disease, and Inflammation Meaning

Understand high IgG4 blood test results, normal ranges, IgG4-related disease symptoms, diagnostic biopsy, treatment, monitoring, and when to seek care.

An IgG4 blood test measures one of the four subclasses of immunoglobulin G, the most abundant antibody class in blood. The test is best...

IgM Blood Test: High, Low, Normal Range, Infection, and Immune Response

Learn how to interpret an IgM blood test, including normal ranges, high and low causes, infection limits, immune deficiency, monoclonal IgM, and next steps.

An IgM blood test measures the concentration of immunoglobulin M in serum. IgM is the antibody class the body can produce rapidly when it...

Immunofixation Blood Test: Monoclonal Protein, Immunoglobulin Type, and Plasma Cell Disorders

Understand serum immunofixation results, monoclonal protein types, IgG, IgA, IgM, kappa and lambda bands, plasma-cell disorders, limitations, and next steps.

A serum immunofixation blood test looks for an abnormal immunoglobulin produced by one clone of plasma cells or B cells. This protein may be...

Immunoglobulin Panel Test: IgG, IgA, IgM, High and Low Levels, and Immune Function

Understand IgG, IgA, and IgM panel results, age-specific ranges, high and low patterns, antibody function, immune deficiency, monoclonal proteins, and follow-up tests.

An immunoglobulin panel measures the main antibody classes circulating in blood: IgG, IgA, and IgM. The panel can show whether antibody concentrations are broadly...

Kappa Light Chain Test: High Levels, Immune Protein, and Monoclonal Gammopathy

Understand high kappa free light chains, assay-specific ranges, kidney effects, kappa/lambda patterns, monoclonal gammopathy, myeloma, amyloidosis, and follow-up tests.

A kappa light chain test measures one component of immunoglobulins, the proteins made by plasma cells to form antibodies. Most clinical orders measure free...

Kappa/Lambda Ratio Test: Abnormal Ratio, Multiple Myeloma, and Plasma Cell Disorders

Learn how to interpret high and low kappa/lambda ratios, kidney-adjusted ranges, MGUS, multiple myeloma biomarkers, amyloidosis, companion tests, and monitoring.

The kappa/lambda ratio compares the two types of free immunoglobulin light chains circulating in blood. Plasma cells normally make both kappa and lambda chains,...

Lambda Light Chain Test: High Levels, Immune Protein, and Monoclonal Gammopathy

Understand high lambda free light chains, kidney and inflammatory effects, low kappa/lambda ratio, monoclonal gammopathy, AL amyloidosis, confirmatory tests, and monitoring.

A lambda light chain test usually measures free lambda immunoglobulin light chains in serum. Plasma cells make lambda or kappa chains as building blocks...

Mannose-Binding Lectin Test: Immune Deficiency Risk, Infections, and Meaning

Understand mannose-binding lectin testing, low MBL results, lectin-pathway function, infection risk, immune deficiency evaluation, and treatment decisions.

A mannose-binding lectin test measures a soluble immune protein or the activity of the complement pathway that it helps start. Mannose-binding lectin, often shortened...

Pneumococcal Antibody Titer Test: Vaccine Response, Immune Function, and Antibody Protection

Understand pneumococcal antibody titers, pre- and post-vaccine testing, serotype IgG thresholds, immune response, antibody deficiency, and next steps.

A pneumococcal antibody titer test measures IgG directed against capsular serotypes of Streptococcus pneumoniae. Clinicians use it for two different purposes: estimating whether antibodies...

Primary Immunodeficiency Blood Test Panel: Immunoglobulins, Complement, Lymphocytes, and Diagnosis

Understand primary immunodeficiency blood testing, immunoglobulins, vaccine responses, lymphocyte subsets, complement, neutrophil function, genetics, and diagnosis.

A primary immunodeficiency blood test panel is not one universal package. It is a staged evaluation chosen from the patient’s infections, immune complications, age,...

Serum Protein Electrophoresis (SPEP) Test: Immunoglobulins, M Protein, and Monoclonal Gammopathy

Understand SPEP patterns, M spikes, monoclonal and polyclonal gammopathy, immunoglobulin regions, MGUS, myeloma testing, interference, and follow-up.

Serum protein electrophoresis, or SPEP, separates blood proteins into bands according to their electrical behavior. Clinicians use the pattern to investigate an unexplained high...

Tetanus Antibody Test: Vaccine Immunity, Protection Level, and Immune Response

Understand tetanus IgG antibody testing, protection thresholds, booster response, vaccine schedules, wound prophylaxis, low titers, immune deficiency, and next steps.

A tetanus antibody test measures IgG against tetanus toxoid, the inactivated toxin used in tetanus-containing vaccines. The result can document a previous vaccine response,...

Vaccine Antibody Titer Test: Immune Protection, IgG Levels, and Vaccine Response

Understand vaccine antibody titers, IgG and IgM results, protection cutoffs, vaccine records, hepatitis B, MMR, varicella, tetanus, pneumococcal response, and immune testing.

A vaccine antibody titer test measures antibodies to one specific vaccine antigen, such as hepatitis B surface antigen, measles virus, tetanus toxoid, or pneumococcal...