Blood Test Guides

eGFR Calculator (CKD-EPI 2021)

Estimate kidney function from creatinine, age and sex using the 2021 race-free CKD-EPI equation, with a toggle for the Japanese (JSN) equation and your CKD stage explained.

LDL Cholesterol Calculator

Estimate LDL from total cholesterol, HDL and triglycerides using the Friedewald and Sampson (NIH) equations, in mg/dL or mmol/L, with how optimal targets vary by guideline.

Labs Normal, Still Tired? The Borderline Markers Standard Panels Miss

Six markers that sit in the "technically normal" zone but are clinically linked to fatigue, brain fog, and low energy, ferritin, Vitamin D, TSH, B12, magnesium, and fasting glucose, and where the borderline zone for each one starts.

Optimal Blood Test Ranges vs. Normal: What's the Real Difference?

"Normal" means you fall inside 95% of a general population, not that a result is ideal. What functional-medicine "optimal" ranges claim, attributed to their sources, and what's actually evidence-backed.

Blood Tests for Fatigue: What to Ask For (and What Standard Panels Miss)

A thorough fatigue workup covers 4 cause clusters: iron status, thyroid function, blood sugar, and nutrients. Here are the specific tests in each cluster, why doctors often skip them, and a script for requesting them.

Blood Tests for Weight Loss: What to Check First

A handful of markers can flag a real obstacle, point you toward the diet that fits your body, or set a baseline to track. The evidence-based read on HbA1c, insulin, thyroid, iron, and vitamin D, plus the baseline labs before a GLP-1.

Blood Tests for Brain Fog: Which Markers to Check

The overlap between brain fog and fatigue is real, but the markers differ. Homocysteine, thyroid antibodies, fasting insulin, and B12 active fraction are the ones most likely missed on a standard workup.

Blood Tests for Low Mood & Depression: What to Ask For

Low mood and low motivation can have physical drivers. Thyroid, vitamin D, B12, folate, and iron are the markers worth ruling out before, or alongside, a mental health workup.

Blood Tests for Anxiety: What to Ask For

Anxiety can have physical drivers a standard panel misses, thyroid dysfunction, blood sugar swings, and magnesium deficiency among them. The tests to ask for before assuming it's purely psychological.

Blood Tests for Hair Loss: What to Ask For

Hair loss has multiple treatable causes that won't show on a standard panel. The specific tests to request, organized by which cause they rule in or out.

Blood Tests for Joint Pain: What to Ask For

Joint pain has several blood-test-detectable causes, inflammation, gout, and autoimmune disease among them. The markers to ask your doctor for and what each one rules in.

Blood Tests for Muscle Weakness & Cramps: What to Ask For

Muscle weakness and cramps often trace to vitamin D, magnesium, potassium, or thyroid. The blood tests that find the cause your standard panel won't flag.

Perimenopause Blood Test Results Explained

FSH, LH, estradiol, and AMH — what each result means, the reference ranges across the transition, and why a single test rarely confirms perimenopause.

Blood Tests for Cold Intolerance: What to Ask For

Always feeling cold can point to an underactive thyroid or iron deficiency. The tests to ask your doctor for before writing it off as "just your circulation."

Blood Tests for Dizziness: What to Ask For

Dizziness and light-headedness can come from anaemia, low blood sugar, or an electrolyte imbalance. The tests that separate one cause from another.

Blood Tests for Frequent Illness & Low Immunity: What to Ask For

Getting sick often or healing slowly can point to a vitamin D, iron, or B12 deficiency. The tests to ask for to find out which.

Blood Tests for Low Libido: What to Ask For

Low libido often has a hormonal or metabolic cause, testosterone, thyroid, iron, or blood sugar. The tests that find the actual driver.

UIBC Blood Test: What High and Low Results Mean

UIBC measures the unused iron-binding capacity in your blood. High UIBC points to iron deficiency. Low UIBC suggests iron overload. Normal range, causes, and what to do next.

Low Ferritin: What It Means, Symptoms, and What to Do

Ferritin depletes months before haemoglobin drops, meaning a normal CBC doesn't rule it out. The borderline zone, what symptoms to expect, causes, and what to do about it.

Low Vitamin D: Why Labs Miss It and What to Fix

The NIH flags insufficiency at 20–29 ng/mL. Most labs only flag below 20. That gap, where millions of results land, is where fatigue, low mood, and immune suppression commonly show up.

High LDL Cholesterol: What It Actually Means for You

LDL above range is not uniform risk. Context, your HDL ratio, triglycerides, family history, and diet, changes the picture significantly. The ACC/AHA classification and when to act.

Low Vitamin B12: Symptoms, Causes, and What to Do

NICE identifies a neurological risk zone at 140–220 pg/mL — below the standard flag threshold. Fatigue, tingling, and brain fog can appear here. The absorption vs. intake distinction determines whether oral supplements will work.

High TSH: What It Means, Symptoms, and When to Act

The normal range goes up to 4.5 mIU/L, but many patients report fatigue, cold intolerance, and brain fog above 2.5. What TSH is actually measuring, the Hashimoto's connection, and what a full thyroid panel includes.

High Triglycerides: What the Number Means and How to Bring It Down

Triglycerides are the most diet-responsive marker on a standard lipid panel, and a stronger insulin resistance signal than LDL alone. Primarily driven by sugar and refined carbs, not dietary fat. 20–50% reductions in 4–8 weeks with targeted changes.

High HbA1c: What It Means and How to Lower It

HbA1c is a 3-month average of blood sugar control. The ADA prediabetes range starts at 5.7%. Here's what different values signal, what lifestyle changes move the needle, and how fast improvement shows up.

HbA1c Blood Test: What Your Result Means

HbA1c measures your 3-month average blood sugar. Here's what normal, prediabetes, and diabetes ranges mean — and the optimal zone most labs don't flag but matters for long-term health.

Fasting Insulin: The Test Not on Your Panel

Fasting insulin is the earliest marker for insulin resistance, often abnormal years before HbA1c flags anything. What the test measures and how to request it.

CRP Blood Test: What a High Result Actually Means

A high CRP confirms inflammation but not its cause. How to interpret your result in context, hs-CRP bands, ESR, ferritin, and acute vs. chronic patterns.

High Creatinine: What It Means and What Else Raises It

High creatinine doesn't always mean kidney disease. Creatine supplements, high protein intake, and dehydration all raise it. How to tell the difference.

Low Magnesium: Why Serum Isn't the Right Marker

Low magnesium symptoms appear before a standard blood test flags anything. Why serum is unreliable, what to test instead, and what low levels cause.

High TSH and Low Ferritin: The Thyroid-Iron Connection

High TSH and low ferritin appearing on the same test is rarely a coincidence. Hypothyroidism directly impairs iron absorption. The mechanism, the right priority order, and what to ask your doctor.

Low Ferritin and High Cholesterol: Why They Often Appear Together

These two markers frequently flag together for the same root cause, often thyroid dysfunction. What the pairing means and what to address first.

Multiple Abnormal Results? 64% of Healthy People Get One

On a 20-marker panel, a healthy person has roughly a 64% chance of at least one abnormal flag by statistics alone. How to tell which of yours actually matter.

4 Signals to Rank Your Abnormal Blood Test Results

Multiple flags, no priority order? Four signals, magnitude, clustering, symptom match, and persistence, decide which abnormal result to fix first.

Abnormal Blood Test Results: Next Steps Guide

Got abnormal results and not sure what to do? What to do next, from reading the flags to knowing when to act urgently vs. monitor.