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Lab testing, explained carefully

Understand the lab test before you act on the result.

Lab Intel builds plain-English, source-aware guides for blood tests, STI testing, genetics, microbiome reports, and emerging biomarkers, with clear boundaries around what a test can and cannot tell you.

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BT

Blood tests

CBC, CMP, BMP, A1C, cholesterol, ApoB, Lp(a), kidney function, liver function, thyroid, iron, vitamins, and inflammation markers.

 STI

STI and STD testing

Testing timing, symptoms, partner exposure, privacy, at-home tests, body-site swabs, HIV PEP, PrEP labs, and confusing exposure questions.

 DNA

Genetics

Direct-to-consumer DNA reports, health claims, clinical confirmation, privacy limits, and when to involve a genetics professional.

 MB

Microbiome

Consumer microbiome reports, gut-health claims, evidence limits, and what to ask before changing diet or supplements.

 BM

Emerging biometrics

Optimization testing, omega-3 index, wearable-adjacent metrics, surrogate markers, and claims that need extra caution.

 ED

Editorial policy

How Lab Intel separates education from diagnosis, uses sources, handles uncertainty, and keeps medical claims bounded.

Recently expanded

New and high-intent guides

STI testing after semen in eye

Rinsing, eye symptoms, HIV PEP timing, STI testing questions, and when to seek care.

 CDC STI testing after semen in mouth

Oral sex, swallowing, throat swabs, HIV anxiety, symptoms, and when testing matters.

 CDC STI testing after semen in throat

Throat swabs, sore throat, pharyngeal gonorrhea, urine-test limits, HIV anxiety, and timing.

 CDC STI testing after semen on tonsils

Tonsils and back-of-throat exposure, throat swabs, sore throat symptoms, HIV anxiety, and timing.

 CDC STI testing after semen on uvula

Back-of-throat exposure, throat swabs, uvula swelling, sore throat symptoms, HIV anxiety, and timing.

 CDC STI testing after semen on roof of mouth

Oral exposure, urine-test limits, throat-swab questions, mouth sores, bleeding, HIV anxiety, and timing.

 CDC STI testing after semen on cheek

Intact cheek skin, eye or mouth contact, cuts, acne wounds, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on chin

Intact chin skin, beard or shaving irritation, cuts, mouth contact, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on forehead

Intact forehead skin, hairline contact, acne or cuts, eye transfer, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on nose

Outer nose skin, nostril contact, nosebleeds, acne or cuts, eye or mouth transfer, HIV anxiety, and symptoms.

 CDC STI testing after semen on neck

Intact neck skin, hickeys, shaving cuts, rash, mouth or eye transfer, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on back

Intact back skin, back acne, scratches, rash, mouth or eye transfer, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on shoulders

Intact shoulder skin, shoulder acne, scratches, sunburn, mouth or eye transfer, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on arms

Intact arm skin, scratches, shaving cuts, rash, sunburn, mouth or eye transfer, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on hands

Intact hand skin, cuts, hangnails, cracked skin, transfer to genitals, mouth or eye, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on chapped hands

Dry versus open chapped skin, bleeding cracks, HIV PEP timing, wound care, transfer, infection signs, and symptoms.

 CDC STI testing after semen on eczema hands

Closed eczema versus raw, bleeding, weeping, cracked, or infected-looking skin, HIV PEP timing, transfer, and wound care.

 NIH STI testing after semen on hand rash

Closed rash versus raw, bleeding, blistered, ulcerated, or infected-looking skin, lesion testing, HIV PEP timing, and transfer.

 CDC STI testing after semen on hand blisters

Closed versus popped, raw, bleeding, clustered, or infected-looking blisters, lesion testing, HIV PEP timing, and transfer.

 CDC STI testing after semen on hand sores

Closed versus open, raw, bleeding, clustered, or infected-looking sores, lesion testing, HIV PEP timing, and transfer.

 CDC STI testing after semen on hand ulcers

Active ulcers, nonintact skin, lesion testing, syphilis and HSV questions, HIV PEP timing, wound care, and transfer.

 CDC STI testing after semen on hand abrasion

Dry versus raw scrapes, nonintact skin, HIV PEP timing, wound care, tetanus, lesion clues, and transfer.

 CDC STI testing after semen on hand scrape

Dry versus raw scraped skin, HIV PEP timing, wound care, tetanus, infection signs, and transfer.

 CDC STI testing after semen on scratched hand

Closed versus open scratches, HIV PEP timing, wound care, tetanus, infection signs, and transfer.

 CDC STI testing after semen on hand scratch

Dry versus open hand scratches, HIV PEP timing, wound care, tetanus, infection signs, and transfer.

 CDC STI testing after semen on scratched skin

Closed versus open scratched skin, HIV PEP timing, wound care, tetanus, body-site transfer, and symptoms.

 CDC STI testing after semen on skin scratch

Closed versus open skin scratches, HIV PEP timing, wound care, tetanus, body-site transfer, and symptoms.

 CDC STI testing after semen on a small cut

Closed versus open small cuts, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a paper cut

Fresh versus sealed paper cuts, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving cut

Fresh versus sealed razor nicks, HIV PEP timing, wound care, tetanus, body-site transfer, and symptoms.

 CDC STI testing after semen on a razor cut

Fresh versus sealed razor cuts, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving nick

Tiny sealed versus open shaving nicks, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a razor nick

Dry versus open razor nicks, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving wound

Closed versus open shaving wounds, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a razor wound

Closed versus open razor wounds, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving abrasion

Healed versus raw scraped skin, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a razor abrasion

Healed versus raw razor-scraped skin, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving scrape

Closed versus raw shaving scrapes, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a razor scrape

Closed versus raw razor scrapes, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving graze

Faint versus raw shaving grazes, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a razor graze

Faint versus raw razor grazes, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving mark

Razor burn versus raw marks, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a razor mark

Razor burn versus raw marks, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on a shaving rash

Razor burn versus raw rash, sores, blisters, HIV PEP timing, wound care, and transfer.

 CDC STI testing after semen on a razor rash

Razor burn versus raw rash, sores, blisters, HIV PEP timing, wound care, and transfer.

 CDC STI testing after semen on razor burn

Closed irritation versus raw skin, HIV PEP timing, lesion checks, wound care, and transfer.

 CDC STI testing after semen on shaving burn

Closed irritation versus raw skin, HIV PEP timing, lesion checks, wound care, and transfer.

 CDC STI testing after semen on razor bumps

Closed bumps versus raw, popped, pus-like, blistered, sore-like, or infected-looking skin.

 CDC STI testing after semen on shaving bumps

Closed bumps versus raw, popped, pus-like, blistered, sore-like, or infected-looking skin.

 CDC STI testing after semen on ingrown hair

Closed ingrown-hair bumps versus raw, popped, pus-like, blistered, sore-like, or infected-looking skin.

 CDC STI testing after semen on folliculitis

Closed follicle bumps versus raw, popped, pus-like, blistered, sore-like, or infected-looking skin.

 CDC STI testing after semen on a boil

Closed skin versus open, draining, raw, bleeding, abscess-like, or infected-looking boils.

 CDC STI testing after semen on an abscess

Closed skin versus open, draining, raw, bleeding, pus-filled, or infected-looking abscesses.

 CDC STI testing after semen on a cyst

Closed skin versus ruptured, draining, raw, bleeding, inflamed, infected-looking, or lesion-like cysts.

 CDC STI testing after semen on a genital lump

Closed bumps, cysts, boils, abscesses, warts, blisters, sores, ulcers, rash, and lesion swabs.

 CDC STI testing after semen on a genital wart

HPV wart diagnosis, why panels do not diagnose warts, raw or bleeding skin, HIV PEP timing, and screening questions.

 CDC STI testing after semen on molluscum

Raised dimpled bumps, what panels miss, genital lesions, spread prevention, raw or bleeding skin, and HIV PEP timing.

 CDC STI testing after semen on a skin tag

Benign skin tags versus warts, molluscum, sores, raw or bleeding skin, body-site exposure, and panel limits.

 CDC STI testing after semen on a mole

Mole changes, intact versus bleeding or scratched skin, skin exam questions, body-site exposure, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a birthmark

Birthmark types, intact versus irritated or bleeding skin, skin exam questions, body-site exposure, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a dermatofibroma

Firm benign bumps, shaving trauma, intact versus bleeding skin, skin exam questions, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a scar

Old scars versus healing wounds, keloids, split or bleeding scar tissue, body-site exposure, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a keloid

Raised scar tissue, intact versus split or bleeding keloids, wound care, body-site exposure, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a hypertrophic scar

Raised scars that stay within the wound boundary, intact versus bleeding skin, wound care, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a piercing scar

Old piercing scars versus healing piercings, keloids, hypertrophic scars, raw or bleeding skin, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a piercing hole

Healed versus fresh or irritated piercing channels, genital and oral sites, infection signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a belly button piercing

Healed navel piercings versus fresh, irritated, bleeding, infected-looking, or jewelry-traumatized channels, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a nipple piercing

Healed versus fresh, torn, bleeding, infected-looking, breast-lump-associated, or breastfeeding-related nipple piercing questions.

 CDC STI testing after semen on an ear piercing

Healed lobes versus fresh, torn, bleeding, infected-looking, cartilage, or perichondritis-type ear piercing questions.

 CDC STI testing after semen on a cartilage piercing

Helix, tragus, conch, daith, rook, and industrial piercings, perichondritis warning signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a helix piercing

Outer-rim cartilage piercings, healed versus fresh or irritated channels, perichondritis warning signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a tragus piercing

Ear-canal-adjacent cartilage piercings, healed versus fresh or irritated channels, perichondritis warning signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a conch piercing

Inner-ear-bowl cartilage piercings, healed versus fresh or pressure-irritated channels, perichondritis warning signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a daith piercing

Innermost cartilage-fold piercings, healed versus fresh or canal-adjacent swelling, perichondritis warning signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a rook piercing

Upper-inner cartilage fold piercings, healed versus fresh or pressure-irritated channels, perichondritis warning signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on an industrial piercing

Two-hole cartilage bar piercings, healed versus fresh or pressure-irritated channels, perichondritis warning signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a lip piercing

Outer lip versus inner mouth exposure, fresh piercing channels, cracked lips, sores, throat swabs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a tongue piercing

Oral exposure, fresh tongue-piercing channels, swelling, sores, throat swabs, HIV PEP timing, dental trauma, and panel limits.

 CDC STI testing after semen on a cheek piercing

Outside cheek skin versus inner-mouth exposure, fresh piercing channels, sores, eye contact, throat swabs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a nose piercing

Outside nose skin versus nostril or septum exposure, fresh piercing channels, sores, eye contact, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a septum piercing

Healed versus fresh septum channels, nasal tissue, sores, eye or mouth transfer, HIV PEP timing, and panel limits.

 CDC STI testing after semen on an eyebrow piercing

Healed versus fresh eyebrow channels, eye proximity, sores, piercing infection signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on a bridge piercing

Bridge-of-nose piercings, healed versus fresh channels, eye proximity, sores, piercing infection signs, HIV PEP timing, and panel limits.

 CDC STI testing after semen on fingers

Intact finger skin, hangnails, under-nail fluid, fingering, transfer to genitals, mouth or eye, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen under fingernails

Under-nail fluid, washing, cuts, hangnails, fingering, transfer to genitals, mouth or eye, HIV anxiety, and pregnancy questions.

 CDC STI testing after semen on cuticle

Intact versus torn cuticles, hangnails, bleeding, paronychia signs, HIV PEP timing, transfer, and wound care.

 CDC STI testing after semen on hangnail

Intact versus torn hangnails, bleeding, raw skin, paronychia signs, HIV PEP timing, transfer, and wound care.

 CDC STI testing after semen on cracked fingertip

Dry versus bleeding fingertip cracks, raw skin, HIV PEP timing, wound care, infection signs, transfer, and symptoms.

 CDC STI testing after semen on cracked knuckle

Dry versus bleeding knuckle cracks, raw skin, HIV PEP timing, wound care, infection signs, transfer, and symptoms.

 CDC STI testing after semen on hand with cut

Fresh versus healed cuts, bleeding, wound care, HIV PEP timing, transfer to genitals or eye, and symptoms.

 CDC STI testing after semen on finger cut

Fresh versus healed finger cuts, torn cuticles, bleeding, wound care, HIV PEP timing, transfer, and symptoms.

 CDC STI testing after semen on open wound

Fresh wounds, cuts, scrapes, burns, ulcers, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on scab

Dry versus cracked, picked, bleeding, or reopened scabs, HIV PEP timing, wound care, infection signs, transfer, and symptoms.

 CDC STI testing after semen on bleeding scab

Nonintact skin, active bleeding, HIV PEP timing, wound care, tetanus, infection signs, transfer, and symptoms.

 CDC STI testing after semen on picked scab

Picked-open scabs, raw or reopened skin, bleeding, HIV PEP timing, wound care, tetanus, transfer, and symptoms.

 CDC STI testing after semen on tongue

Oral exposure, throat swabs, urine-test limits, HIV anxiety, mouth sores, and symptoms.

 CDC STI testing after semen on gums

Bleeding gums, gum disease, oral exposure, throat swabs, HIV anxiety, and symptoms.

 CDC STI testing after semen on lips

Intact lips, mouth exposure, cracked lips, cold sores, HIV anxiety, and symptoms.

 CDC STI testing after semen on face

Cheeks, mouth, eyes, HIV anxiety, pregnancy questions, symptoms, and when testing matters.

 CDC STI testing after semen on chest

Chest, breasts, nipples, HIV anxiety, pregnancy questions, symptoms, and when testing matters.

 CDC STI testing after semen on stomach

Abdomen skin, HIV anxiety, pregnancy questions, symptoms, and when testing matters.

 CDC STI testing after semen on pubic hair

Hair, intact skin, HIV anxiety, pregnancy questions, symptoms, and when testing matters.

 CDC ApoB and Lp(a) blood tests

Advanced lipid markers, inherited risk, particle risk, and result caveats.

 AHA Kidney function tests

eGFR, creatinine, BUN, UACR, kidney-risk context, preparation, and result caveats.

 NIDDK Omega-3 index test

EPA, DHA, red blood cell fatty acids, supplement caveats, and evidence limits.

 NIH
See every guide View llms.txt

Core guides

Reliable starting points for common decisions

Bloodwork and biomarker basics

CBC blood test

Complete blood count markers and interpretation context.

Guide Basic metabolic panel

Glucose, calcium, electrolytes, BUN, creatinine, and BMP versus CMP.

Guide Comprehensive metabolic panel

Glucose, electrolytes, kidney markers, liver markers, proteins, and calcium.

Guide A1C test

Average blood sugar, diabetes and prediabetes ranges, prep, and limits.

Guide Lipid panel

LDL, HDL, triglycerides, total cholesterol, fasting, and risk context.

Guide

Sexual health testing basics

STI testing guide

When to test, what tests cover, self-collection, and follow-up questions.

Guide Full STI panel

What panels include, what they miss, body-site testing, herpes, timing, and follow-up.

Guide HIV testing window period

Test types, timing after exposure, negative results, and follow-up testing.

Guide Chlamydia and gonorrhea testing

Urine, swabs, throat and rectal testing, and retesting.

Guide Extragenital STI testing

Throat and rectal swabs, urine-test limits, and site-of-contact testing.

Guide