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Heart & Circulation

High Sensitivity C-Reactive Protein (hs-CRP)

hs-CRP is a marker of low-level inflammation in your blood. Ongoing low-grade inflammation is linked to heart risk, so the test can add context to a broader heart-health assessment. You are probably hoping for a simple "is my number OK?", and the honest answer is that hs-CRP does not give you that on its own — Australian guidelines do not recommend it for routine cardiovascular screening, and your GP reads it alongside your cholesterol, blood pressure, and overall health picture. This page explains what the number means and what to ask about.

Targeted Testing
CategoryHeart & Circulation
Reference rangeSee your report
Evidence○Targeted Testing
Last updated3 July 2026
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What is high sensitivity c-reactive protein (hs-crp)?

C-reactive protein (CRP) — a protein your liver releases when there is inflammation somewhere in your body — is normally tested in its high-sensitivity form (hs-CRP) when a doctor wants to pick up very low levels of background inflammation that a standard CRP test would miss. Inflammation is part of your body's normal defences, but ongoing low-grade inflammation — even without obvious symptoms — has been associated with cardiovascular disease (CVD) over time. hs-CRP is most useful when read alongside your lipids (cholesterol and triglycerides), blood pressure, age, and other risk factors, rather than as a standalone reading.

Why is it tested?

hs-CRP is sometimes ordered as part of a cardiovascular risk assessment for people at intermediate risk, where one more piece of information might help a GP decide on next steps. It can also be raised by infection, autoimmune conditions, and other inflammatory states — which is why your GP interprets it in context rather than in isolation. It is worth knowing that the 2023 Australian guideline for assessing and managing cardiovascular disease (CVD) risk does not include hs-CRP as a recommended factor. The guideline notes it adds little beyond the standard Australian CVD risk calculator. That makes it a test for specific situations, not a general population screening tool.

Reference range (Australia)

Below 1 mg/L lower cardiovascular risk; 1–3 mg/L average; above 3 mg/L higher risk mg/L

These cardiovascular risk bands come from the AHA/CDC (an international source), not from Australian guidelines, and are interpretive categories rather than a laboratory "normal" range. The 0–20 mg/L figure sometimes shown is the assay's measurement cap, not a risk threshold. Australian guidance does not endorse hs-CRP for routine cardiovascular screening, so use the reference interval on your report and discuss the result with your GP.

Reference intervals vary between laboratories. Always use the range printed on your own report.

What your result means

If your level is low

A low hs-CRP suggests minimal background inflammation — a favourable finding for cardiovascular health. It can reflect healthy habits, genetics, or both. A low result does not remove all cardiovascular risk; cholesterol, blood pressure, and family history still matter independently.

If your level is in range

An in-range hs-CRP suggests your background inflammation is within typical limits. Your cardiovascular risk still depends on your overall picture — lipids, blood pressure, age, smoking status, and family history — which your GP assesses using the Australian CVD risk calculator rather than any single marker.

If your level is high

A higher-than-range hs-CRP means your body has measurable inflammation at the time of testing. In a cardiovascular context, higher levels are associated with greater inflammatory load — but a single raised result cannot tell you whether you have heart disease, and it is not specific to the heart. Infection, physical stress, injury, poor sleep, excess body weight, or autoimmune conditions can all push it up. If your result is raised and you have recently been unwell, your GP may suggest repeating the test once you have fully recovered — an acute infection, even a mild cold, can raise hs-CRP substantially and temporarily, and the lower second reading is the one used for cardiovascular risk assessment. Your GP reads it alongside your cholesterol, blood pressure, and overall profile.

What can affect your result

Body composition, activity, diet, infection, stress, sleep, and underlying conditions all influence hs-CRP. Physical inactivity and excess body weight — particularly around the abdomen — are associated with higher levels. Regular aerobic activity and a Mediterranean-style diet are associated with lower levels. Recent infection is worth flagging: even a mild cold can raise hs-CRP markedly and temporarily, which is why your GP asks about recent illness when a result is raised. Chronic stress, poor sleep, and smoking are also associated with higher levels. Autoimmune or chronic inflammatory conditions raise hs-CRP persistently, rather than in spikes. Because so many factors move the number, a single reading needs context before it means much.

When to act

If your hs-CRP is raised, it is worth a conversation with your GP. They will ask whether you have had a recent infection, illness, or injury — if so, repeating the test once you are fully well is the standard approach, and the lower second reading is the one used for risk assessment. If it stays raised after recovery, your GP assesses your overall cardiovascular risk using the Australian CVD risk calculator and may suggest lifestyle measures such as regular activity, a heart-healthy diet, achieving a healthy weight, not smoking, and better sleep. hs-CRP alone is not a basis for changing any medication — it is one piece of a broader picture. This page is general information and is not a substitute for advice from your GP.

Frequently asked questions

International cardiovascular guidance from the AHA/CDC (the American Heart Association and Centers for Disease Control and Prevention) describes three categories: below 1 mg/L is lower risk, 1–3 mg/L is average, and above 3 mg/L is higher risk. These are interpretive categories, not a laboratory reference range — your report will list its own interval. The 2023 Australian guideline notes hs-CRP adds little beyond the standard Australian risk calculator, so your GP reads it in the context of your full cardiovascular profile, not in isolation.

No. A raised hs-CRP indicates measurable inflammation, which is associated with higher cardiovascular risk at a population level — but it cannot tell you whether you have heart disease on its own. It can be raised by a recent infection, poor sleep, excess weight, or autoimmune conditions. Your GP considers it alongside your cholesterol, blood pressure, age, smoking status, and family history before drawing any conclusions.

Yes, and quite significantly. Any acute infection — even a mild cold — can raise hs-CRP substantially and temporarily. If you were unwell in the weeks before testing, your GP may suggest retesting once you have fully recovered. The lower of the two readings is the one used for cardiovascular risk assessment.

No. The 2023 Australian guideline for assessing and managing cardiovascular disease (CVD) risk does not include hs-CRP as a recommended factor, and notes it provides little extra value beyond the standard Australian CVD risk calculator. Australian Prescriber similarly states that using hs-CRP to refine cardiac risk assessment is not routinely recommended. Your GP may still order it when it would genuinely add useful context for a specific decision.

Lifestyle does appear to play a role. Regular aerobic activity, a Mediterranean-style diet, achieving a healthy weight, not smoking, managing stress, and better sleep are all associated with lower hs-CRP — though individual responses vary and changes can take weeks to months to show up. If hs-CRP stays raised despite these changes, your GP can discuss what else might be driving it.

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