Evidence-Based Supplement & Herb Guides

Germline Genetic Testing: Inherited Mutations, Family Risk, and Results

Learn how germline genetic testing identifies inherited variants, explains family risk, distinguishes positive and negative results, and guides cascade testing and follow-up.

Germline genetic testing looks for DNA variants that were present from conception and can potentially be passed to children. These variants are usually found...

Mitochondrial DNA (mtDNA) Test: Mutations, Inheritance, and Results

Understand what an mtDNA test detects, how heteroplasmy and tissue choice affect results, what maternal inheritance means, and what to do after a positive, uncertain, or negative finding.

A mitochondrial DNA test looks for harmful changes in the small circle of DNA inside mitochondria, the energy-producing structures found in nearly every cell....

Newborn Genetic Screening Test: Conditions, Results, and Follow-Up

Learn how newborn genetic screening works, which conditions it checks, what abnormal and normal results mean, and how repeat testing and urgent follow-up protect a baby’s health.

Newborn screening is a public health program that checks babies for serious conditions before symptoms are obvious. In the United States, it usually includes...

Pharmacogenetic Testing: Medication Response, Gene Variants, and Results

Understand how pharmacogenetic testing links gene variants to medication response, how metabolizer results are interpreted, which gene–drug pairs are actionable, and how to use results safely.

Pharmacogenetic testing examines inherited DNA variants that can influence how a person processes or responds to certain medicines. A useful result may help a...

Polygenic Risk Score (PRS) Test: Disease Risk, DNA Markers, and Results

Learn how a polygenic risk score combines DNA markers, what percentiles and absolute risk mean, where PRS testing may help, and why ancestry, calibration, and clinical context matter.

A polygenic risk score estimates inherited susceptibility to a common disease by combining the effects of many DNA markers. Unlike a single-gene test that...

Predictive Genetic Testing: Disease Risk, Results, and What It Means

Understand predictive genetic testing, including who may benefit, why an affected relative is usually tested first, what positive and negative results mean, and how results affect care and family.

Predictive genetic testing looks for inherited variants associated with a disease that a person does not currently have. It can identify an increased chance...

Prenatal Genetic Testing: Screening, Diagnosis, Risk, and Results

Compare prenatal genetic screening with CVS and amniocentesis, understand cell-free DNA and diagnostic results, and learn how timing, test scope, false positives, and follow-up affect care.

Prenatal genetic testing can estimate or diagnose certain chromosome and gene conditions during pregnancy. Screening tests—such as cell-free DNA, first-trimester screening, and the second-trimester...

Presymptomatic Genetic Testing: Inherited Disease Risk and Results

Understand presymptomatic genetic testing, who may consider it, how positive and negative results affect inherited disease risk, and what happens next.

Presymptomatic genetic testing looks for a known disease-causing genetic change in someone who does not currently have symptoms of the condition. It is most...

Single-Gene Genetic Test: Mutation Results, Disease Risk, and Meaning

Learn how single-gene genetic tests work, what pathogenic, negative, and VUS results mean, how they affect disease risk, and why test method matters.

A single-gene genetic test examines one selected gene because the medical question points strongly to that gene or because a specific familial condition is...

Somatic Genetic Testing: Tumor Mutations, Cancer Treatment, and Results

Learn how somatic genetic testing finds tumor mutations, guides cancer treatment, uses tissue or liquid biopsy, and distinguishes actionable from uncertain results.

Somatic genetic testing examines acquired changes in cancer cells. These changes develop during a person’s lifetime and help distinguish tumor cells from most normal...

Tumor Genomic Testing: Cancer Mutations, Targeted Therapy, and Results

Understand tumor genomic testing, how cancer mutations are matched to targeted therapy, what result categories mean, and why an actionable target may not work.

Tumor genomic testing creates a molecular profile of cancer by examining genes, DNA changes, RNA alterations, and sometimes genome-wide biomarkers that may influence diagnosis...

Variant of Uncertain Significance (VUS): Genetic Test Results and Meaning

Learn what a variant of uncertain significance means, why VUS results occur, what they should not change, how reclassification works, and what to ask next.

A variant of uncertain significance, or VUS, is a DNA change for which current evidence cannot show whether it contributes to disease or is...

Whole-Exome Sequencing (WES) Test: Genetic Diagnosis, Variants, and Results

Understand whole-exome sequencing, who may benefit, how trio analysis works, what positive and negative results mean, and why reanalysis can find answers later.

Whole-exome sequencing, usually abbreviated WES or ES, analyzes most protein-coding regions of thousands of genes at the same time. These regions are called exons...

Whole-Genome Sequencing (WGS) Test: DNA Variants, Disease Risk, and Results

Understand what whole-genome sequencing tests, what positive, negative, and uncertain WGS results mean, its limitations, disease-risk findings, privacy issues, and next steps.

Whole-genome sequencing (WGS) examines nearly all of a person’s DNA in a single test. Unlike tests limited to one gene, a gene panel, or...

X-Linked Genetic Test: Inheritance Pattern, Carrier Risk, and Results

Learn how X-linked genetic tests identify variants, how inheritance and carrier risk work, what positive, negative, and VUS results mean, and which follow-up steps matter.

An X-linked genetic test looks for a disease-related change in a gene on the X chromosome. The result can help diagnose symptoms, confirm whether...

Alpha-1 Antitrypsin Deficiency Genetic Test: SERPINA1, Liver, Lung, and Results

Learn how SERPINA1 genetic testing, AAT blood levels, and protein phenotyping diagnose alpha-1 antitrypsin deficiency and guide lung, liver, and family follow-up.

An alpha-1 antitrypsin deficiency genetic test examines the SERPINA1 gene for variants that lower the amount or function of alpha-1 antitrypsin, often shortened to...

APOB Genetic Test: High LDL Cholesterol, Heart Risk, and Results

Understand how APOB genetic testing can identify LDL-raising familial hypercholesterolemia or LDL-lowering hypobetalipoproteinemia and how results guide treatment and family screening.

An APOB genetic test looks for inherited variants in the gene that makes apolipoprotein B, the main structural protein on LDL and several other...

APOE Genotype Test: Cholesterol, Alzheimer Disease Risk, and Results

Understand APOE ε2, ε3, and ε4 genotype results for cholesterol, late-onset Alzheimer susceptibility, and ARIA risk before anti-amyloid treatment.

An APOE genotype test identifies which two common APOE alleles—ε2, ε3, or ε4—a person inherited. APOE helps move cholesterol and other fats through the...

Arrhythmogenic Cardiomyopathy Genetic Test: PKP2, DSP, DSG2, and Results

Learn how PKP2, DSP, DSG2, and other arrhythmogenic cardiomyopathy genetic results are interpreted and used for diagnosis, exercise counseling, treatment, and family screening.

An arrhythmogenic cardiomyopathy genetic test looks for inherited variants that weaken heart-cell connections or alter other pathways involved in ventricular rhythm and muscle structure....

Brugada Syndrome Genetic Test: SCN5A Gene, Heart Rhythm Risk, and Results

Learn how the SCN5A genetic test supports Brugada syndrome diagnosis, what positive, negative, and uncertain results mean, and how findings guide fever precautions, treatment, and family screening.

Brugada syndrome is an inherited electrical heart disorder that can increase the risk of dangerous ventricular rhythms, fainting, cardiac arrest, and sudden death. Its...