Oral Glucose Tolerance Test (OGTT): When to Order This Test
A complete clinical guide to the OGTT: who needs it, what the numbers mean, how to interpret gestational and non-gestational results, and what to do when values are abnormal.
Omega-3 Index Interpretation by Decade of Life
A guide to omega-3 index normal ranges, optimal targets, and how EPA+DHA red-blood-cell levels should be interpreted differently across each decade of life.
Omega-3 While Fasting: Does It Affect Your Index?
Fasting is not required for an Omega-3 Index test and does not meaningfully change your result. Diet and supplement dose are what drive your number.
Omega-3 Index: Lab "Normal" vs Functional Optimal Explained
Understand an Omega-3 Index result, the 4% and 8% research thresholds, laboratory target ranges, food and supplement labels, and when retesting is useful.
Omega-3 Index: When to Order This Test
Learn when clinicians order the Omega-3 Index test, what EPA+DHA levels in red blood cells mean for cardiovascular risk, and how to interpret results, with primary-source citations throughout.
Pituitary MRI Indication: Which Tests to Order Alongside
A guide to the lab workup that triggers a pituitary MRI order, the paired tests required before and after imaging, and how to interpret results in context of prolactin, cortisol, and other pituitary axes.
Progesterone Interpretation by Decade of Life
A decade-by-decade clinical guide to progesterone normal ranges, optimal targets, and how to interpret lab results from adolescence through post-menopause, with primary-source citations throughout.
Progesterone, Training, and Exercise: What Your Levels Mean for Performance and Recovery
How exercise intensity, training phase, and hormonal cycling affect progesterone levels in women and men, with normal ranges, optimal targets, and clinical guidance from HealthRX.com.
Resting Heart Rate: What This Test Actually Measures
A complete clinical guide to resting heart rate, what it measures, normal ranges, causes of high and low readings, and evidence-based ways to improve it. prepared by the HealthRX.com Editorial Team.
Reverse T3: How to Interpret Your Result
Learn what your Reverse T3 lab result means, what the normal range is, and what high or low levels tell you about thyroid function, stress, and metabolism.
Reverse T3, Nutrition, and Fasting: What the Evidence Actually Shows
How fasting, caloric restriction, low-carb diets, and specific nutrient deficiencies drive Reverse T3 up, what the normal and optimal ranges mean, and the clinical steps to bring RT3 back down.
Selenium: Which Tests to Order Alongside a Selenium Level
A guide to interpreting serum selenium results and the companion lab panel every provider should order: thyroid function, glutathione peroxidase, iodine, and more.
SHBG: How to Interpret Your Result
A guide to reading your SHBG lab result, understanding normal ranges, and knowing when high or low SHBG requires treatment. Includes free testosterone context, diagnosis thresholds, and actionable next steps.
SHBG: What This Test Actually Measures
A complete clinical guide to sex hormone-binding globulin (SHBG): what it binds, why free hormone fractions matter, normal ranges, causes of high and low levels, and how diet, medications, and lifestyle shift the number.
SHBG: When to Order This Test, What Results Mean, and How to Act on Them
A clinical guide to sex hormone-binding globulin (SHBG): when clinicians order the test, what high or low values indicate, normal ranges by sex and age, and evidence-based strategies to adjust levels.
SIBO Breath Test: Sex- and Cycle-Related Differences in Normal Ranges and Results
How estrogen, progesterone, and menstrual-cycle phase affect SIBO breath test hydrogen and methane readings, with evidence-based normal ranges and clinical interpretation for women and men.
SIBO Breath Test: Normal Ranges, Optimal Targets, and What Longevity Medicine Recommends
A guide to SIBO breath test interpretation, covering hydrogen and methane cutoffs, longevity-medicine target ranges, and what to do when results fall outside normal.
SIBO Breath Test: What "Normal" Means vs. What Functional Optimal Actually Looks Like
Learn what your SIBO breath test numbers really mean, how clinical 'normal' differs from functional optimal, and what gas thresholds indicate hydrogen, methane, or hydrogen-sulfide overgrowth.
Polysomnography Interpretation: What Your AHI Score Means
See AHI, oxygen, and sleep-stage ranges from your polysomnography report, from normal (AHI under 5) to severe OSA (AHI 30+), with treatment thresholds explained.
Polysomnography (Sleep Study): Normal vs. Functional Optimal Results Explained
Learn what polysomnography (sleep study) results actually mean, the difference between lab 'normal' and functional optimal, and how sleep-disordered breathing affects hormone health, testosterone, and metabolic function.
Polysomnography 4 or More Parameters: What Your Results Mean
See normal AHI, sleep efficiency, REM and N3 ranges, plus how much change between sleep studies signals real progression or improvement.
Sterol Balance (Boston Heart): How to Interpret Your Result
Learn what your Boston Heart Sterol Balance result means, what normal ranges look like, and whether you are an absorber or a producer, with clinical guidance on how to act on the number.
Sterol Balance (Boston Heart): Which Tests to Order Alongside
A guide to interpreting the Boston Heart Sterol Balance panel, understanding absorber vs. Producer phenotypes, and selecting the right companion labs to personalize statin, ezetimibe, and dietary therapy.
Comprehensive Stool Analysis: Evidence-Based Ways to Improve Your Results
A guide to understanding comprehensive stool analysis results, what abnormal findings mean, and the specific diet, supplement, and lifestyle interventions backed by primary research.
Comprehensive Stool Analysis: Medication-Driven Changes Explained
How prescription and over-the-counter drugs alter comprehensive stool analysis results, including dysbiosis markers, leaky gut indicators, and SIBO-related findings, with normal and optimal ranges, clinical interpretation, and when to retest.
Comprehensive Stool Analysis: Which Tests to Order Alongside
A guide explaining what comprehensive stool analysis measures, how to interpret results, and which paired labs (zonulin, SIBO breath test, calprotectin, GI-MAP, organic acids, and more) give the clearest picture of gut health.
Thyroglobulin Antibodies: Drugs That Distort This Test, Normal Ranges, and What Results Mean
Which medications raise or lower thyroglobulin antibody (TgAb) levels, what a normal TgAb range looks like, and how to interpret high or low results in thyroid autoimmunity and post-thyroidectomy monitoring.
How to Lower Thyroglobulin Antibodies (Evidence-Based)
No drug is FDA-approved to lower TgAb. Selenium has the best trial support; vitamin D, TSH control, and gluten-free diets help in specific cases.
TgAb Biomarker Test - What Your Result Means
TgAb above 1 to 4 IU/mL signals autoimmune thyroid disease or cancer recurrence risk. Learn normal ranges, causes, and what undetectable means after thyroidectomy.
TPO Antibodies: Longevity-Medicine Target Ranges and What Your Results Mean
What are optimal TPO antibody levels for longevity medicine? Learn the standard normal range, Hashimoto's autoimmunity thresholds, and evidence-based target ranges prepared by the HealthRX.com Editorial Team.
TPO Antibodies: Lab 'Normal' vs Functional Optimal Explained
What TPO antibody levels mean, where lab 'normal' ends and clinically meaningful risk begins, how these antibodies drive Hashimoto's thyroiditis, and what the evidence actually supports for lowering them.
TPO Antibodies Most Common in Hashimoto's - What It Means
TPO (anti-TPO) antibodies are the most frequent autoimmune marker in Hashimoto's thyroiditis, positive in 90 to 95% of patients. See what your number means.
TMAO Drugs That Distort This Test: What Medications Skew Your Trimethylamine N-Oxide Results
A clinical guide to drugs, supplements, and dietary factors that raise or lower TMAO levels, interfere with accurate testing, and how to interpret trimethylamine N-Oxide results correctly.
TSH: How to Interpret Your Result
A guide to reading your TSH lab result, understanding what high and low values mean, and knowing when to act.
TSH: When to Order This Test, What Results Mean, and How to Act on Them
A guide to TSH testing: who needs it, what normal and abnormal results mean, when to retest, and how thyroid-stimulating hormone guides treatment decisions for hypothyroidism and hyperthyroidism.
UACR Test Kit: At-Home Options, Normal Range & Targets
Compare at-home UACR test kits with lab accuracy. Normal is under 30 mg/g; longevity-focused clinicians target under 10 mg/g. See collection steps and thresholds.
UACR 39 Meaning - What This Result Indicates by Age
UACR 39 mg/g falls in the microalbuminuria range (30-300), above the normal <30 cutoff and well above the optimal <10 target. See interpretation by age decade.
Urine Albumin/Creatinine Ratio: What Your Number Changes About Your Treatment
Learn what your urine albumin/creatinine ratio (uACR) means, what the normal range is, and exactly how each result category triggers different clinical decisions for diabetes, hypertension, and kidney disease management.
Urine Albumin/Creatinine Ratio: Evidence-Based Ways to Improve This Number
Learn what your urine albumin/creatinine ratio means, what a normal range looks like, and which diet, medication, and lifestyle strategies have the strongest clinical evidence for lowering it.
UACR Urine Test: Key Factors to Evaluate and What They Mean
UACR categories, meaningful progression thresholds, and KDIGO 2024 recheck intervals explained, grouped by normal, A2, and A3 albuminuria levels.
ACTH Interpretation by Decade of Life
A decade-by-decade guide to ACTH normal ranges, optimal values, and clinical interpretation for adrenal function, HPA axis health, and longevity medicine.
Adiponectin Longevity-Medicine Target Ranges
What adiponectin levels actually predict longevity outcomes, how to interpret your lab result against research-backed target ranges, and when to act on a low value.
Aldosterone Longevity-Medicine Target Ranges: What Your Lab Result Actually Means
A guide to aldosterone normal ranges, longevity-medicine optimal targets, primary aldosteronism screening, and how to interpret your results in the context of cardiovascular and metabolic health.
Drugs Affecting Aldosterone/Renin Ratio (ARR) and Test Accuracy
ACE inhibitors, ARBs, diuretics, beta-blockers and hormonal therapy skew ARR results. See which drugs raise or suppress aldosterone before testing.
Alkaline Phosphatase Longevity-Medicine Target Ranges
What alkaline phosphatase levels predict the longest, healthiest life? A guide to optimal ALP ranges, isoenzyme interpretation, and evidence-based longevity targets.
Alkaline Phosphatase Calf Intestinal - What Your ALP Level Means
Intestinal ALP peaks 2 to 4 hours after a fatty meal, especially in blood groups B and O. Reference range is 44-147 IU/L; longevity target is 50-100 IU/L.
ANA Nutrition and Fasting Impact: What You Eat (and Don't Eat) Before Your Test
Does fasting change your ANA result? Learn how nutrition, fasting status, supplements, and diet affect antinuclear antibody testing, what a normal ANA range looks like, and how to get the most accurate result.
ApoB Longevity-Medicine Target Ranges: What the Evidence Actually Says
ApoB is a more accurate cardiovascular risk predictor than LDL-C. Learn what optimal ApoB levels look like in longevity medicine, what major trials show, and what target ranges leading guidelines recommend.
ApoB, Training, and Exercise: What the Evidence Actually Shows
Does exercise lower ApoB? A detailed clinical review of how aerobic training, resistance work, and combined protocols affect ApoB levels, with dose thresholds, timelines, and what to expect from your next lipid panel.
AST Interpretation by Decade of Life: Normal Range, Optimal Levels, and What Your Number Really Means
A decade-by-decade clinical guide to AST (aspartate aminotransferase) interpretation, covering normal ranges, optimal targets, the AST/ALT ratio, and when to act on an abnormal result.
AST Longevity-Medicine Target Ranges: What Optimal Looks Like Beyond 'Normal'
Aspartate aminotransferase (AST) reference ranges flag disease, but longevity medicine asks a sharper question: what AST level is associated with the lowest all-cause mortality and best metabolic health? This guide covers the evidence, the AST/ALT ratio, and the numbers your clinician should be targeting.
How Long Do Liver Enzymes Stay Elevated After Exercise
AST can rise 2 to 5x normal after intense training and usually returns to baseline within 72 hours. Learn the AST/ALT ratio that separates muscle from liver causes.
Bioavailable Testosterone by Age: How to Interpret Your Lab Results by Decade of Life
A guide to bioavailable testosterone normal ranges, optimal targets, and what declining levels mean at every decade from your 20s through your 70s and beyond.
Bioavailable Testosterone: Sex- and Cycle-Related Differences, Normal Ranges, and Optimal Levels
A guide to bioavailable testosterone reference ranges for men and women across the menstrual cycle and life stages, with primary-source citations and actionable clinical targets.
Bioavailable Testosterone, Training, and Exercise: What the Lab Number Actually Means
A guide to bioavailable testosterone, how exercise changes it, what the optimal range looks like, and when a low result should prompt treatment.
24-Hour Ambulatory BP Rate-of-Change Interpretation
How to read your 24-hour ambulatory blood pressure report: normal ranges, dipper status, rate-of-change thresholds, and what masked hypertension means for your cardiovascular risk.
C-Peptide, Nutrition, and Fasting: What Your Levels Really Mean
How diet, fasting, and meal timing shift C-peptide levels, what the normal and optimal ranges mean, and how clinicians use C-peptide to distinguish insulin resistance from beta-cell failure.
C-Peptide Rate-of-Change Interpretation: What Your Labs Actually Mean
A guide to interpreting C-peptide rate-of-change, normal ranges, optimal targets, and what a rising or falling trend means for beta-cell health, insulin resistance, and diabetes classification.
CAC Score and Exercise: How Training Affects Coronary Calcium
Does exercise raise or lower your coronary artery calcium score? Evidence from clinical trials, society guidelines, and longevity medicine on how training impacts CAC scores and cardiovascular risk.
Continuous Glucose Monitor (CGM) Interpretation by Decade of Life
How to read CGM data at every age, what target ranges come from guidelines versus clinical practice patterns, and a decision framework for choosing the right target tier based on age-related hypoglycemia risk.