Vitamin D Test: What Level Is Actually Deficient and Who Needs Testing
A vitamin D test measures 25-hydroxyvitamin D in blood. Most US laboratories and the NIH call a level below 12 ng/mL (30 nmol/L) deficient…
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Blog Category
Screening & Prevention
Articles on screening and prevention: which cancer, heart and metabolic tests are recommended, at what age and how often, and what happens when a screening result is abnormal.
Preventive Care Checklist: The Screenings and Vaccines Recommended by Age
Preventive care is the set of screenings, vaccines and counseling that find or prevent disease before symptoms appear. For most adults that means blood…
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Whole Genome Sequencing and Polygenic Risk Scores: What Consumer Genomics Can Predict
Whole genome sequencing reads nearly all 3 billion letters of a person's DNA and can reliably identify rare single-gene variants linked to conditions such…
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Protein in Urine: What a Urinalysis Finding Means for Your Kidneys
Protein in urine, called proteinuria, means the kidneys' filters are letting protein such as albumin leak through. A single positive result on a urinalysis…
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Lynch Syndrome: The Inherited Cancer Risk Worth Knowing About
Lynch syndrome is an inherited condition, caused by a change in one of the DNA mismatch repair genes, that raises lifetime risk of colorectal,…
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Genetic Testing: What It Can Detect and How Long Results Take
Genetic testing can detect single-gene conditions such as cystic fibrosis, sickle cell disease and Huntington disease, chromosome differences such as Down syndrome, inherited cancer…
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Pap Smear vs HPV Test: What Each Detects and the New Screening Intervals
A Pap smear examines cervical cells under a microscope for abnormal changes, while an HPV test looks for the genetic material of high-risk human…
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A Short History of DNA Testing, and How Long a Test Takes Today
Modern DNA testing began in September 1984, when British geneticist Alec Jeffreys developed DNA fingerprinting at the University of Leicester; the first criminal conviction…
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Food Sensitivity Tests: Why IgG Kits Fail the Evidence Test
Food sensitivity tests that measure IgG antibodies to foods are not supported by current evidence. IgG against a food usually signals normal exposure and…
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CRP and ESR: The Inflammation Blood Tests Explained
A CRP test measures C-reactive protein, a substance the liver releases within hours when the body is inflamed by infection, injury or inflammatory disease.…
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Celiac Testing: The Blood Tests, the Biopsy, and Why You Must Not Go Gluten-Free First
Celiac disease is diagnosed in two steps: a blood test that looks for antibodies, most often tissue transglutaminase IgA (tTG-IgA), followed, for most adults,…
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Calprotectin Stool Test: How It Separates IBS From Inflammatory Bowel Disease
Calprotectin is a protein released by white blood cells into the gut when the bowel lining is inflamed. A stool test measures it in…
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FibroScan: The Liver Stiffness Test Explained
FibroScan is a painless, non-invasive scan that uses a brief vibration and ultrasound to measure how stiff the liver is, reported in kilopascals (kPa),…
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The PSA Test: What Levels Mean by Age, and Why Context Is Everything
There is no single normal PSA. Commonly used age-referenced upper limits are roughly 2.5 ng/mL for men in their 40s, 3.5 in their 50s,…
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The FIT Test: Home Stool Screening That Actually Works
The fecal immunochemical test (FIT) is a yearly at-home colorectal cancer screening that uses antibodies to detect hidden blood in a small stool sample.…
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Gut Microbiome Tests: What the Science Supports and What It Does Not, Yet
At-home gut microbiome tests can describe which bacteria appear in a stool sample, but current evidence does not show they can diagnose disease, predict…
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EKG Explained: What the 12 Leads Show and What ‘Abnormal’ Usually Means
An EKG (electrocardiogram, also written ECG) records the heart's electrical activity for about ten seconds using ten electrodes that produce twelve views, or leads,…
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Hearing Tests: What an Audiogram Measures and When to Have One
A hearing test measures the quietest sound you can hear at each pitch, usually from low rumbles around 250 hertz to high whistles near…
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