Format: what it is → why it's ordered → what results roughly mean, in plain language. This is a reference panel — patients will land here from condition pages or search directly for a test they were just given. This page covers blood tests specifically; for ECG, Holter monitors, echo, MRI, nuclear imaging, and stress testing, see Cardiac Testing & Imaging.
Complete Blood Count (CBC)
Measures your red blood cells, white blood cells, and platelets. In cardiology, it's used to check for anemia (low red blood cells, which can worsen heart failure symptoms and mimic them), infection (elevated white cells), and bleeding risk (platelet count), especially relevant if you're on blood thinners.
Comprehensive Metabolic Panel (CMP)
A panel of blood tests covering kidney function, electrolytes (sodium, potassium), liver function, and blood sugar. Heart and kidney function are closely linked, and several heart medications (diuretics, ACE inhibitors/ARBs/ARNI, MRAs) directly affect electrolytes and kidney values — this is why it's checked regularly, not just at diagnosis. (If your potassium has run high or low, see Potassium Diet for the dietary guidance behind it.)
Magnesium
Magnesium isn't part of the standard CMP, so it's ordered separately when there's a specific reason to check it. It's an electrolyte essential for normal heart rhythm, muscle function, and nerve signaling — low levels (hypomagnesemia) can cause muscle cramps, tremor, fatigue, and, importantly, dangerous heart rhythm problems. It's checked especially often in people taking loop or thiazide diuretics (which increase magnesium loss through the kidneys) and in heart transplant recipients on calcineurin-inhibitor anti-rejection medications (tacrolimus, cyclosporine), both well-recognized causes of ongoing magnesium loss. Because magnesium and potassium levels often move together, and low magnesium can make it harder to correct low potassium, your care team may check both at the same time. (See Magnesium Diet for food sources and practical guidance.)
NT-proBNP (and BNP)
A hormone released by a stretched or strained heart. Elevated levels support a heart failure diagnosis and help track whether you're retaining fluid; trending it over time (rather than one isolated number) is often more useful than a single result, since your personal baseline matters.
High-Sensitivity Troponin (hs-Troponin)
A protein released when heart muscle cells are injured. It's the key blood test for diagnosing a heart attack, but can also be mildly elevated in other conditions that stress the heart (severe heart failure, kidney disease, very fast heart rhythms) — so an elevated troponin always needs to be interpreted alongside your symptoms and other testing, not read alone.
Lipid Panel (including ApoB and Lp(a))
Measures total cholesterol, LDL ("bad" cholesterol), HDL ("good" cholesterol), and triglycerides. Two more specialized markers are increasingly used for a fuller risk picture:
- ApoB — counts the actual number of cholesterol-carrying particles in your blood, which can be more precise than LDL alone for assessing risk, especially if your triglycerides are high
- Lp(a) — a genetically-determined cholesterol particle that raises cardiovascular risk independent of lifestyle; it's typically checked once in a lifetime, since it doesn't change much with diet or exercise, but knowing it helps your doctor judge your overall risk and treatment intensity
High-Sensitivity C-Reactive Protein (hs-CRP)
A marker of inflammation in the body, measured with a more sensitive test than the standard CRP used to check for infection. Chronic low-grade inflammation plays a real role in the buildup of arterial plaque, so hs-CRP is sometimes used, alongside your other risk factors, to help refine a borderline cardiovascular risk estimate — it's one of the recognized Hyperlipidemia risk-enhancing factors. It's not a routine screening test for everyone; it's most useful for people whose risk category is genuinely unclear based on standard factors alone, and it can be falsely elevated by any recent infection, injury, or inflammatory condition unrelated to your heart, so timing and context matter when it's checked.
Uric Acid
A waste product filtered by your kidneys, most commonly known for its role in gout. In cardiology, elevated uric acid has an independent, well-documented association with higher cardiovascular risk, hypertension, and heart failure, though it's used more as an additional piece of your overall risk picture than as a stand-alone treatment target. It commonly rises with several diuretics (a recognized side effect worth knowing about if you're on one), with kidney disease, and with diets high in red meat, organ meat, shellfish, and alcohol (especially beer). If your level is elevated, your care team will consider it alongside your other risk factors and medications rather than treating the number in isolation.
Glucose Tests (Fasting Glucose & HbA1c)
Fasting glucose is a snapshot of your blood sugar at one moment; HbA1c reflects your average blood sugar over roughly the past 2–3 months. Both matter in cardiology because diabetes and prediabetes significantly raise cardiovascular risk, and several modern heart failure medications (SGLT2 inhibitors) benefit the heart and blood sugar together.
INR (International Normalized Ratio)
Measures how long your blood takes to clot, specifically used to monitor and adjust the dose of warfarin, one of the anticoagulant ("blood thinner") medications. A higher number means your blood clots more slowly. (See Anticoagulants for target ranges by condition and how dosing adjustments work.)
Quick Reference: Typical Adult Normal Ranges
Use this as a general orientation, not a diagnosis — normal ranges vary somewhat between labs, and your own target range may differ based on your specific condition and medications. Always interpret your results with your care team, not this table alone.
| Test | Typical Normal Range* | Notes |
|---|---|---|
| NT-proBNP | Roughly under 125 pg/mL (varies by age) | Rises with age and heart strain; your own trend matters more than one value |
| High-Sensitivity Troponin | Very low or undetectable | Any meaningful rise is interpreted alongside symptoms and an ECG |
| Total Cholesterol | Under 200 mg/dL (general guide) | Your target may be lower depending on your individual risk |
| LDL ("bad" cholesterol) | Under 100 mg/dL (general guide) | Often set much lower for people with known heart disease |
| HDL ("good" cholesterol) | Above roughly 40 mg/dL (men), 50 mg/dL (women) | Higher is generally more favorable |
| Triglycerides | Under 150 mg/dL | Strongly affected by diet, alcohol, and blood sugar control |
| Potassium | Roughly 3.5–5.0 mEq/L | Monitored closely with several heart failure and blood pressure medications |
| Magnesium | Roughly 1.7–2.2 mg/dL | Checked especially with diuretics and after heart transplant |
| High-Sensitivity CRP | Under 1.0 mg/L (low added risk) | 1.0–3.0 mg/L average added risk; above 3.0 mg/L higher added risk |
| Uric Acid | Roughly 3.5–7.2 mg/dL (varies by sex) | Also affected by diet, alcohol, and several diuretics |
| Fasting Glucose | Under 100 mg/dL | 100–125 is prediabetes range; 126+ on repeat testing suggests diabetes |
| HbA1c | Under 5.7% | 5.7–6.4% is prediabetes range; 6.5%+ suggests diabetes |
| INR (on warfarin) | Individualized — commonly 2.0–3.0 | Your specific target depends on why you're taking warfarin; ask your care team for your target |
\Ranges shown are general adult reference points meant for orientation only — your lab report's own reference range, and your care team's interpretation, always take precedence over this table.*