Evidence-Based Supplement & Herb Guides

Rett Syndrome Genetic Test: MECP2 Gene Mutations and Results

Learn how MECP2 sequencing, deletion testing, mosaicism, and result categories support a Rett syndrome diagnosis, family counseling, and care planning.

A Rett syndrome genetic test looks mainly for disease-causing changes in MECP2, a gene on the X chromosome that helps regulate how nerve cells...

Spinal Muscular Atrophy (SMA) Genetic Test: SMN1, SMN2 Copy Number, and Results

Understand SMA genetic testing, including SMN1 and SMN2 copy number, silent-carrier risk, newborn screening, diagnostic results, and family next steps.

A spinal muscular atrophy genetic test usually measures copies of SMN1, the gene whose loss causes most 5q SMA, and SMN2, a closely related...

Spinocerebellar Ataxia Genetic Test: CAG Repeat Expansions and Results

Learn how spinocerebellar ataxia CAG repeat testing works, what repeat ranges mean, why assay methods matter, and how results guide care and families.

A spinocerebellar ataxia CAG repeat test measures repeated CAG DNA units in specific genes associated with inherited ataxia. Common targets include ATXN1, ATXN2, ATXN3,...

Cell-Free DNA (cfDNA) Test: Prenatal Screening, Cancer, and Transplant Results

Learn how cell-free DNA testing is used for prenatal screening, cancer mutation analysis, and transplant monitoring, including result meanings, limitations, and follow-up.

A cell-free DNA test analyzes short DNA fragments that circulate outside cells, most often in blood plasma. The same basic specimen can answer very...

Chromosomal Microarray Test: Copy Number Variants, Deletions, and Duplications

Understand how chromosomal microarray detects deletions and duplications, what pathogenic and uncertain CNV results mean, what CMA misses, and when follow-up testing is needed.

A chromosomal microarray test scans DNA for missing or extra segments called copy number variants. It can find many deletions and duplications that are...

Copy Number Variant (CNV) Test: Deletions, Duplications, and Results

Learn how copy number variant tests detect deletions and duplications, how methods differ, what pathogenic and uncertain CNV results mean, and which follow-up tests may be needed.

A copy number variant test looks for sections of DNA that are present in fewer or more copies than expected. These changes range from...

Deletion/Duplication Genetic Test: Copy Number Variants and Results

Learn how deletion/duplication genetic testing finds missing or extra exons, how MLPA and NGS dosage analysis work, and what positive, negative, and uncertain results mean.

A deletion/duplication genetic test checks whether one or more parts of a gene are missing or present in extra copies. It is often ordered...

Digital PCR (dPCR) Test: Low-Level Mutations, Copy Number, and Results

Learn how digital PCR detects rare mutations and measures copy number, including partition counting, detection limits, result units, false signals, and follow-up.

Digital PCR measures a specific DNA or RNA target by dividing a sample into thousands of tiny reactions and counting how many contain the...

Fluorescence In Situ Hybridization (FISH) Test: Gene Deletions, Duplications, Fusions, and Results

Learn how FISH testing uses fluorescent probes to detect gene deletions, duplications, amplifications, and fusions, including signal patterns, cutoffs, and limitations.

Fluorescence in situ hybridization, or FISH, uses colored DNA probes to locate selected chromosome or gene regions inside cells. A pathologist or cytogenetic technologist...

Gene Fusion Test: Cancer Rearrangements, Fusion Genes, and Results

Gene fusion testing detects cancer-related rearrangements that can clarify diagnosis and guide targeted therapy; learn how RNA, DNA, FISH, PCR, and results differ.

A gene fusion test looks for abnormal joins between two genes or between different parts of the same gene. These rearrangements can create a...

Karyotype Test: Chromosome Number, Structure, and Results

Karyotype testing counts chromosomes and detects large structural changes; understand balanced rearrangements, mosaicism, notation, limitations, and next steps.

A karyotype test examines whole chromosomes under a microscope to evaluate their number and large-scale structure. It can identify an extra or missing chromosome,...

Liquid Biopsy Test: Circulating Tumor DNA, Cancer Mutations, and Results

Liquid biopsy testing analyzes circulating tumor DNA for cancer mutations, treatment targets, resistance, and residual disease; learn how positive and negative results differ.

A liquid biopsy analyzes tumor-related material in blood or another body fluid. In routine precision oncology, the term most often refers to testing plasma...

Loss of Heterozygosity (LOH) Test: Tumor Genetics and Results

Loss of heterozygosity testing identifies locus-specific or genome-wide allelic loss in tumors; learn about copy-neutral LOH, HRD scores, limitations, and results.

Loss of heterozygosity, or LOH, describes a tumor region that has lost the normal difference between the two chromosome copies inherited from each parent....

Methylation Genetic Test: Imprinting Disorders, Cancer, and Results

Methylation genetic testing detects imprinting abnormalities, constitutional episignatures, and cancer profiles; learn how methods, mosaicism, and result types differ.

A methylation genetic test measures chemical marks attached to DNA rather than changes in the DNA letter sequence alone. DNA methylation helps regulate whether...

Microsatellite Instability (MSI) Test: DNA Repair, Cancer Risk, and Results

Microsatellite instability testing evaluates mismatch repair in tumors for treatment and Lynch syndrome screening; learn about MSI-high, MSS, IHC, and follow-up.

A microsatellite instability test evaluates whether a tumor has accumulated abnormal length changes in short repetitive DNA sequences called microsatellites. These errors usually arise...

Mitochondrial DNA Sequencing Test: mtDNA Mutations and Results

Mitochondrial DNA sequencing detects mtDNA variants and heteroplasmy; learn how tissue choice, maternal inheritance, deletions, VUS findings, and negative results affect interpretation.

Mitochondrial DNA sequencing examines the small circular genome inside mitochondria, the cell structures that generate much of the body’s usable energy. Pathogenic mtDNA variants...

Multigene Panel Test: Inherited Disease Genes, Cancer Genes, and Results

Multigene panel testing analyzes inherited disease and cancer genes together; learn how panel selection, coverage, pathogenic variants, VUS findings, and negative results are interpreted.

A multigene panel test analyzes several or many genes at the same time. It is useful when different genes can cause overlapping symptoms or...

Multiplex Ligation-Dependent Probe Amplification (MLPA) Test: Gene Deletions, Duplications, and Results

MLPA testing detects targeted gene deletions and duplications; learn how the assay works, how results are interpreted, why findings need confirmation, and what a negative result means.

Multiplex ligation-dependent probe amplification, usually called MLPA, is a targeted molecular test used to measure the number of copies of selected DNA regions. It...

Next-Generation Sequencing (NGS) Test: Gene Panels, Variants, and Results

Understand how next-generation sequencing tests analyze gene panels, exomes, and genomes, what pathogenic, negative, and VUS results mean, and where NGS can miss variants.

Next-generation sequencing (NGS) is a laboratory method that reads millions of DNA or RNA fragments in parallel. In clinical care, it can examine many...

Polymerase Chain Reaction (PCR) Test: DNA Amplification, Variants, and Results

Learn how PCR tests amplify DNA or RNA, what positive, negative, Ct, and invalid results mean, and why sample quality, timing, and assay design affect accuracy.

A polymerase chain reaction (PCR) test searches for a specific genetic target by making many copies of that target in the laboratory. The starting...