Evidence-Based Supplement & Herb Guides

Autoimmune Disease Genetic Risk Test: HLA, Immune Genes, and Results

Learn what an autoimmune disease genetic risk test measures, how HLA and immune-gene results are interpreted, and why positive or negative findings do not provide a diagnosis.

An autoimmune disease genetic risk test looks for inherited DNA differences linked to conditions in which the immune system attacks the body’s own tissues....

Common Variable Immunodeficiency (CVID) Genetic Test: Immune Disorder Genes and Results

Learn how CVID genetic testing examines immune-disorder genes, what positive, negative, and uncertain results mean, and when a molecular diagnosis may change care.

A common variable immunodeficiency genetic test searches for inherited or newly occurring DNA variants that can cause a CVID-like immune disorder. It may examine...

Complement Deficiency Genetic Test: Immune System Genes and Results

Learn how complement deficiency genetic testing evaluates immune-system genes, how CH50 and AH50 guide diagnosis, and what positive, negative, or uncertain results mean.

A complement deficiency genetic test looks for DNA variants that reduce, eliminate, or dysregulate proteins in the complement system. Complement is a network of...

Crossmatch Test: Transplant Compatibility, Positive Result, and Meaning

Learn how CDC, flow cytometry, and virtual crossmatch tests assess transplant compatibility, what a positive result means, and why donor-specific antibodies affect risk.

A transplant crossmatch test estimates whether a recipient’s antibodies are likely to attack cells from a specific donor. A negative crossmatch generally supports immunologic...

Donor-Specific Antibody (DSA) Test: Transplant Rejection Risk and Results

Understand donor-specific antibody testing, including positive and negative DSA results, MFI, rejection risk, crossmatch findings, limitations, and follow-up after transplant.

A donor-specific antibody test looks for antibodies that recognize human leukocyte antigen, or HLA, markers carried by a particular organ or stem-cell donor. These...

Familial Mediterranean Fever Genetic Test: MEFV Gene, Inflammation, and Results

Learn how MEFV testing supports familial Mediterranean fever diagnosis, including variants, carrier results, colchicine treatment, and amyloidosis risk.

A familial Mediterranean fever genetic test looks for variants in the MEFV gene, which provides instructions for making pyrin, a protein that helps regulate...

Hereditary Angioedema Genetic Test: SERPING1, F12, PLG, and Results

Understand hereditary angioedema genetic testing for SERPING1, F12, PLG, and other genes, including result meanings, inheritance, complement tests, and emergency care.

A hereditary angioedema genetic test looks for inherited variants that can cause repeated swelling through excessive bradykinin activity. The most common form involves SERPING1,...

HLA Antibody Test: Transplant Compatibility, PRA, and Results

Understand HLA antibody testing, including PRA and cPRA, MFI, sensitization, donor-specific antibodies, transplant compatibility, limitations, and follow-up results.

An HLA antibody test checks blood for antibodies against human leukocyte antigen markers. These antibodies can develop after pregnancy, blood transfusion, or a previous...

HLA Matching Test: Kidney, Bone Marrow, Organ Transplant, and Results

Understand HLA matching for kidney, bone marrow, stem-cell, and organ transplant, including 6/6, 8/8, 10/10, haploidentical, mismatch, antibody, and crossmatch results.

An HLA matching test compares inherited human leukocyte antigen markers between a transplant recipient and a potential donor. The meaning of a “good match”...

HLA Typing Test: Immune Matching, Transplant, Disease Risk, and Results

Understand HLA typing methods, allele names, resolution, transplant matching, disease associations, drug-reaction risk, specimen issues, and result interpretation.

An HLA typing test identifies a person’s inherited human leukocyte antigen variants. HLA proteins guide immune recognition, so typing is used to match transplant...

HLA-A Genetic Test: Tissue Type, Transplant Matching, and Results

Understand HLA-A genetic testing, including allele names, tissue type, transplant matching, donor-specific antibodies, disease associations, drug risk, and result limitations.

An HLA-A genetic test identifies the two inherited alleles at the HLA-A locus, one of the major class I human leukocyte antigen genes. HLA-A...

HLA-A*31:01 Test: Carbamazepine Hypersensitivity Risk and Results

Understand HLA-A*31:01 testing for carbamazepine hypersensitivity, including positive and negative results, HLA-B*15:02 differences, drug decisions, and urgent symptoms.

The HLA-A31:01 test checks for an inherited immune-system allele associated with a higher risk of carbamazepine hypersensitivity. Carbamazepine is used for epilepsy, trigeminal neuralgia,...

HLA-B Genetic Test: Tissue Type, Drug Reaction Risk, and Results

Understand HLA-B genetic testing for tissue type, transplant matching, drug reaction alleles, HLA-B27 and HLA-B51 disease risk, result notation, and limitations.

An HLA-B genetic test identifies inherited alleles at the HLA-B locus, one of the most variable immune-system genes in humans. The same gene can...

HLA-B27 Test: Ankylosing Spondylitis Risk, Positive Result, and Meaning

Understand HLA-B27 testing for ankylosing spondylitis and axial spondyloarthritis, including positive and negative results, symptoms, imaging, related conditions, and next steps.

The HLA-B27 test checks whether a person carries an HLA-B allele group strongly associated with axial spondyloarthritis, including ankylosing spondylitis. It is a supporting...

HLA-B51 Test: Behcet Disease Risk and Results

Understand HLA-B51 testing for Behçet disease risk, including positive and negative results, HLA-B5 differences, clinical diagnosis, symptoms, limitations, and next steps.

The HLA-B51 test checks for an inherited HLA-B allele group associated with Behçet disease, a relapsing inflammatory disorder that can affect the mouth, genitals,...

HLA-B*15:02 Test: Carbamazepine Skin Reaction Risk and Results

Understand HLA-B*15:02 testing before carbamazepine, including who needs it, positive and negative results, SJS/TEN risk, medication choices, and urgent rash signs.

The HLA-B15:02 test checks whether a person carries an immune-system allele strongly linked to carbamazepine-induced Stevens–Johnson syndrome and toxic epidermal necrolysis. These rare reactions...

HLA-B*57:01 Test: Abacavir Hypersensitivity Risk and Results

Learn how HLA-B*57:01 testing prevents abacavir hypersensitivity, what positive and negative results mean, when to test, symptoms to recognize, and how results guide HIV treatment.

The HLA-B*57:01 test identifies people at high risk of an immune-mediated hypersensitivity reaction to abacavir, an antiretroviral medicine used in some HIV treatment combinations....

HLA-B*58:01 Test: Allopurinol Severe Skin Reaction Risk and Results

Learn how HLA-B*58:01 testing estimates allopurinol severe skin-reaction risk, who may need testing, what results mean, safer dosing, alternatives, and urgent warning signs.

The HLA-B*58:01 test checks for an inherited immune-system allele strongly associated with allopurinol-induced severe cutaneous adverse reactions. These reactions include Stevens–Johnson syndrome, toxic epidermal...

HLA-C Genetic Test: Tissue Type, Immune Matching, and Results

Understand HLA-C genetic testing for tissue type, stem cell matching, donor-specific antibodies, KIR ligands, allele results, mismatches, limitations, and transplant follow-up.

An HLA-C genetic test identifies the two HLA-C alleles a person inherited and helps describe immune-system tissue type. HLA-C is a class I human...

HLA-DP Genetic Test: Immune Matching and Results

Understand HLA-DP genetic testing, including DPA1 and DPB1 alleles, permissive mismatches, stem cell donor selection, donor-specific antibodies, results, and limitations.

An HLA-DP genetic test identifies inherited HLA-DPA1 and HLA-DPB1 alleles that combine to form HLA-DP class II molecules. These molecules present protein fragments to...