What to Do With Your Blood Test Results
Getting blood test results can be confusing and sometimes alarming. This guide walks you through how to read your results, what the flags mean, when to call your doctor, and how to take action on findings that are in your control.
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Get My Score →Step 1: Read the Flags — But Understand What They Mean
Blood test reports use H (high) and L (low) flags to mark results outside the laboratory's reference range. These ranges are set at the 2.5th–97.5th percentile of the population tested at that laboratory. By statistical design, approximately 5% of healthy people will have at least one "flagged" result on any given panel. A single out-of-range value requires context — not panic.
Step 1: Distinguish Flags From Clinical Significance
A result outside the lab reference range has an H or L flag — but not all flags are equally important. A ferritin of 11 ng/mL (flagged low) and a ferritin of 28 ng/mL (within range) both represent suboptimal iron stores but carry very different urgency. Context matters: how far outside range, trend over time, and whether you have symptoms.
| Scenario | What It Means | What To Do |
|---|---|---|
| One mildly flagged result on a large panel | Likely normal variation — especially if borderline and no symptoms | Retest in 3–6 months; discuss with doctor if persistent |
| Multiple related abnormalities (e.g. ALT + AST + GGT all elevated) | Pattern suggests a real finding — liver disease, metabolic syndrome, alcohol effect | Discuss with doctor; further testing likely needed |
| Markedly abnormal single result (e.g. potassium 6.5 mEq/L, or haemoglobin 7 g/dL) | Potentially urgent — requires prompt clinical assessment | Contact your doctor same day or attend urgent care |
| Critical values (e.g. glucose above 600, sodium below 120) | Potentially life-threatening | Lab will typically call your doctor or you directly — emergency care if symptomatic |
Step 2: Look for Patterns, Not Individual Values
A single flagged value is less informative than a pattern across multiple markers. Mildly elevated ALT alongside elevated triglycerides, low HDL, and elevated fasting glucose forms a metabolic syndrome pattern — far more actionable than isolated ALT elevation. Understanding how blood test values cluster is the difference between a list of numbers and a meaningful health picture. Clariti's analysis tool helps identify these patterns across your full panel.
Step 3: Distinguish What Is Urgent, What Needs Monitoring, and What Is Actionable
Urgent (contact your doctor within 24 hours): markedly elevated potassium or sodium, very low or very high glucose, haemoglobin below 8 g/dL, significantly elevated calcium, troponin elevation, INR above 4. Monitor and retest (discuss at next appointment): mildly elevated liver enzymes, borderline cholesterol, TSH mildly elevated, ferritin mildly low, vitamin D mildly low. Actionable now without a doctor: vitamin D deficiency (supplement 2,000–5,000 IU daily), iron deficiency without anaemia (ferritin 15–30 ng/mL — increase dietary iron and vitamin C), elevated triglycerides (reduce refined carbohydrates and alcohol).
How to Prepare a Useful Conversation With Your Doctor
Uploading Results to Clariti
Rather than interpreting each number individually, upload your blood test PDF to Clariti. The system extracts and scores each biomarker against research-based optimal ranges (not just lab reference ranges), identifies patterns, and produces a plain-language health score. This is particularly useful for annual results where tracking trends over time is more meaningful than any single snapshot.
Medical Disclaimer
This article is for educational purposes only and does not constitute medical advice. Reference ranges, supplement dosages, and nutritional information mentioned are general educational guidance from published research—not personalised recommendations. Do not use this content to self-diagnose or self-treat any condition. Always consult a qualified healthcare provider before making any changes to your health regimen, medications, or supplements.
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