Evidence-Based Supplement & Herb Guides

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...

Real-Time PCR (qPCR) Test: Genetic Variants, Viral DNA, and Results

Understand how real-time PCR detects genetic variants and viral DNA, how Ct, Cq, and viral-load values are interpreted, and why assay design and sample quality affect results.

Real-time polymerase chain reaction, usually called qPCR, detects and tracks a selected DNA target while amplification is happening. Fluorescent signals rise as the target...

Repeat Expansion Test: CAG, CGG, CTG Repeats, and Results

Learn how CAG, CGG, CTG, and other repeat expansion tests work, how repeat counts are classified, and what positive, intermediate, premutation, and negative results mean.

A repeat expansion test measures how many times a short DNA sequence is repeated at a specific gene or chromosome location. Repeats such as...

RNA Expression Panel Test: Gene Activity, Cancer Risk, and Results

Understand how RNA expression panels measure tumor gene activity, create recurrence or risk scores, and guide selected cancer-treatment decisions while accounting for sample quality and limitations.

An RNA expression panel measures the activity of a selected group of genes in a tissue sample. Instead of asking whether a DNA mutation...

RNA Sequencing Test: Gene Expression, Fusions, and Results

RNA sequencing measures gene activity and can detect fusions, abnormal splicing, and expression changes. Learn how RNA-seq works, what results mean, and its limits.

RNA sequencing, often called RNA-seq, examines the RNA molecules that cells produce when genes are active. Unlike DNA testing, which mainly identifies inherited or...

Sanger Sequencing Test: Single-Gene Variants and Results

Sanger sequencing reads targeted gene regions to find or confirm small DNA variants. Understand chromatograms, result categories, limitations, and follow-up testing.

Sanger sequencing is a focused DNA test that reads the order of bases in a selected gene region. It is often used when a...

Single-Gene Sequencing Test: DNA Variants, Diagnosis, and Results

Single-gene sequencing searches one selected gene for DNA variants. Learn when focused testing is useful, what results mean, what may be missed, and next steps.

A single-gene sequencing test looks for disease-related DNA variants in one selected gene. It is most useful when a person’s symptoms, biochemical findings, imaging,...

SNP Genotyping Test: DNA Variants, Risk Markers, and Results

SNP genotyping tests selected DNA markers for traits, medication response, and disease risk. Learn how genotypes and polygenic scores work, their limits, and follow-up.

SNP genotyping tests identify selected single-nucleotide polymorphisms—positions in DNA where people commonly differ by one base. A test may examine one medically important variant,...

Structural Variant Genetic Test: Inversions, Translocations, and Results

Structural variant tests detect inversions, translocations, and complex chromosome changes. Learn which methods find balanced and unbalanced events and what results mean.

Structural variant genetic testing looks for large rearrangements in DNA, including inversions, translocations, insertions, deletions, duplications, and complex combinations of these events. Unlike a...

Targeted Variant Test: Known Mutation, Family Testing, and Results

Targeted variant testing checks relatives for a known family mutation. Learn who should test, what positive and true-negative results mean, and how to follow up.

A targeted variant test answers a narrow genetic question: is a specific, already identified DNA change present in this person? It is commonly used...

Variant Classification in Genetic Testing: Pathogenic, Benign, VUS, and Results

Genetic variant classification labels findings as pathogenic, likely pathogenic, VUS, likely benign, or benign. Learn the evidence behind each category and reclassification.

Variant classification is the process laboratories use to decide whether a DNA change is likely to cause disease. Most clinical germline reports use five...

Whole-Exome Sequencing (WES) Method: Coding DNA, Variants, and Results

Whole-exome sequencing examines most coding DNA for rare disease variants. Learn how WES works, what trio results mean, what it can miss, and when reanalysis helps.

Whole-exome sequencing, or WES, examines most of the protein-coding regions of thousands of genes at once. These regions, called exons, make up only a...

Whole-Genome Sequencing (WGS) Method: DNA Variants, Structural Changes, and Results

Whole-genome sequencing detects coding, noncoding, copy-number, and structural DNA variants. Learn how WGS works, what results mean, its blind spots, and reanalysis.

Whole-genome sequencing, or WGS, reads DNA across coding and noncoding regions instead of capturing mainly exons. A clinical genome can be analyzed for single-base...