LabCorp Blood Test Results Explained: A Complete Guide

How LabCorp Reports Are Formatted

LabCorp results come through their Patient portal or as a PDF summary. Each test shows your result next to a reference range — the range represents what most healthy people score. Results outside the range are flagged with an H (above range) or L (below range).

LabCorp groups tests into panels. A standard annual physical typically includes a Comprehensive Metabolic Panel (CMP), Complete Blood Count (CBC), and often a lipid panel. Additional tests like thyroid (TSH), HbA1c, or vitamin D may be added depending on what your doctor ordered.

One important note: LabCorp and Quest use slightly different reference ranges for some tests, and their normal ranges don't always reflect research-backed optimal values. A result within the reference range can still be in a suboptimal zone for long-term health.

Comprehensive Metabolic Panel (CMP)

The CMP is the most ordered panel in the US — it appears on almost every annual physical. It covers blood sugar, kidney function, liver health, and electrolytes in 14 tests.

Glucose (blood sugar): The most important single number for metabolic health. LabCorp's fasting reference range is 70–99 mg/dL. Pre-diabetes is 100–125 mg/dL. If you're above 99 mg/dL, even borderline, it's worth tracking closely — pre-diabetes is largely reversible with dietary changes.

eGFR (Kidney function): LabCorp calculates your estimated Glomerular Filtration Rate directly on the report. Above 60 mL/min/1.73m² is generally normal. Values between 30–59 indicate moderate kidney impairment. Values above 90 are optimal for most adults under 65.

BUN and Creatinine: Two waste products that accumulate when kidneys aren't filtering efficiently. LabCorp's reference for creatinine is 0.74–1.35 mg/dL for men and 0.59–1.04 mg/dL for women. Elevated creatinine alongside low eGFR strengthens the picture of kidney stress.

Liver enzymes (ALT, AST, ALP): ALT and AST are released into the bloodstream when liver cells are damaged. Mild elevations (under 2x the upper reference) are common with fatty liver, alcohol consumption, or intense exercise. ALP can also be elevated with bone conditions, not just liver issues.

Electrolytes: Sodium, potassium, chloride, and CO2 (bicarbonate) maintain fluid balance and support nerve and muscle function. These typically only flag abnormal in specific medical conditions, but low potassium (under 3.5 mEq/L) is worth noting — it's more common than people realize and affects energy and heart rhythm.

Complete Blood Count (CBC)

The CBC is a count of the cells in your blood. It's divided into three types: red blood cells, white blood cells, and platelets.

Hemoglobin and Hematocrit: These are the two main anemia markers. LabCorp's reference for hemoglobin is 13.2–17.1 g/dL for men and 11.7–15.5 g/dL for women. Low hemoglobin almost always points to iron deficiency in otherwise healthy adults, especially women. If flagged low, request a ferritin test — ferritin measures your iron stores and is a more sensitive early indicator of deficiency than hemoglobin alone.

White Blood Cells (WBC): The normal range is 3.8–10.8 thousand/μL on LabCorp reports. Elevated WBC indicates your immune system is active — often due to infection, inflammation, or sometimes just physical stress. A significantly elevated count (above 15–20) warrants urgent follow-up.

Platelets: LabCorp's reference is 140–400 thousand/μL. Platelets enable blood clotting. Very low platelet counts (thrombocytopenia) can increase bleeding risk. A single slightly low result is often not concerning, but a downward trend over multiple tests should be discussed with your doctor.

Lipid Panel

LabCorp's lipid panel reports total cholesterol, LDL, HDL, and triglycerides. These should be interpreted together as a cardiovascular risk picture, not individually.

LDL Cholesterol: LabCorp flags above 130 mg/dL as high. The American Heart Association's optimal target for adults without heart disease is under 100 mg/dL. For those with existing cardiovascular disease, under 70 mg/dL is recommended. If your LDL is in the 100–129 range, it's technically "near optimal" on your report but worth addressing through diet and lifestyle.

HDL Cholesterol: Unlike other cholesterol markers, you want HDL high. LabCorp flags under 40 mg/dL in men as low. Optimal is above 60 mg/dL. HDL is raised most effectively through aerobic exercise, losing excess body fat, and reducing refined carbohydrates.

Triglycerides: LabCorp's normal is under 150 mg/dL. Under 100 mg/dL is optimal. High triglycerides alongside low HDL is a classic marker of metabolic syndrome and insulin resistance, even if glucose is still in the normal range.

Other Common LabCorp Tests

TSH (Thyroid Stimulating Hormone): LabCorp's reference is 0.450–4.500 μIU/mL. Many functional medicine practitioners prefer to see TSH between 1.0–2.0 μIU/mL as optimal. High TSH suggests the thyroid is underactive (hypothyroidism); low TSH suggests overactivity (hyperthyroidism).

HbA1c: This reflects your average blood sugar over the previous three months. LabCorp's reference shows under 5.7% as normal, 5.7–6.4% as pre-diabetes, and 6.5%+ as diabetes. For longevity and metabolic health, many clinicians aim for 5.0–5.4%.

Vitamin D (25-OH): LabCorp's reference range is 30–100 ng/mL. Many researchers suggest 40–60 ng/mL is optimal. Vitamin D deficiency is extremely common in the US — studies estimate 40–50% of American adults have insufficient levels.

How to Use Your LabCorp Results Effectively

The most valuable thing you can do with your LabCorp report is track it over time. A one-off result gives you a snapshot; results from multiple years give you a trend. Trends reveal whether your health is improving or deteriorating — before symptoms appear.

Upload your LabCorp PDF to Clariti to get a plain-English score across six health domains: cardiovascular, metabolic, kidney, liver, blood, and inflammatory health. It takes 30 seconds and costs nothing.