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Blood test

hs-CRP test

hs-CRP test: what it measures, why a doctor orders it, how to prepare, and what a high or low result can mean - with private and NHS access routes in the UK.

Key facts

At a glance

  • What it measures: C-reactive protein using a high-sensitivity assay able to detect the low-grade inflammation linked to cardiovascular risk.

  • Why it is ordered: to refine cardiovascular risk assessment rather than to diagnose infection - the standard CRP test does that job.

  • No fasting or special preparation is needed for this test on its own.

  • Reference ranges: cardiovascular risk bands are described at much lower concentrations than the standard CRP interval. Every laboratory publishes its own interval, so the range printed on your report is the one that applies to you.

  • A raised result suggests low-grade background inflammation associated with higher cardiovascular risk, provided infection and injury have been excluded. A low result indicates little background inflammation and is favourable.

  • Results are usually back within 24-48 hours when taken privately, and often the same day for urgent requests.

The full picture

What this test tells you, and how to get it

The hs-CRP test measures C-reactive protein using a high-sensitivity assay able to detect the low-grade inflammation linked to cardiovascular risk. Doctors most often request it to refine cardiovascular risk assessment rather than to diagnose infection - the standard CRP test does that job. No fasting or special preparation is needed for this test on its own. Cardiovascular risk bands are described at much lower concentrations than the standard CRP interval, and reference intervals genuinely differ between laboratories, so no single number should be treated as a universal cut-off - your result is always read against the range printed on your own report. Broadly, a raised result suggests low-grade background inflammation associated with higher cardiovascular risk, provided infection and injury have been excluded, while a low result indicates little background inflammation and is favourable, and either finding is interpreted alongside your symptoms, medication and other results rather than in isolation. Results are usually back within 24-48 hours when taken privately, and often the same day for urgent requests.

In the UK there are two routes to this test. Your NHS GP can arrange it free of charge when it is clinically indicated, though getting the appointment, the blood draw and the follow-up discussion can add days to weeks depending on local demand. Privately, the hs-CRP test can usually be booked within days - through a private GP, a walk-in phlebotomy clinic or a self-request home-testing service - within advanced heart-health panels. A private result still deserves a clinician's interpretation: an isolated number without context is where most confusion about blood tests begins.

A quiet reminder

This guide is for information, not medical advice.

Your own clinician knows your history and can tell you which parts apply to you. Reference ranges vary between laboratories - always read your result against the interval printed on your own report. Next review of this page: 2027-09-27.

Frequently asked

Common questions about hs-CRP test.

Quick, plain-English answers to what people ask us most.

  • What is the hs-CRP test?

    hs-CRP stands for high-sensitivity C-reactive protein, a blood test that measures low levels of inflammation in the body more precisely than a standard CRP test. It is often used to assess cardiovascular risk rather than to detect acute infection.

  • Why would a doctor order an hs-CRP test?

    It is commonly used as part of cardiovascular risk assessment, since chronic low-grade inflammation is linked to increased risk of heart disease, particularly in people whose other risk factors, like cholesterol, are borderline or unclear.

  • Do I need to prepare for an hs-CRP test?

    No fasting is typically required, though it is best to avoid testing during an acute illness or infection, as this can raise the result for reasons unrelated to cardiovascular risk. Your clinic may advise rescheduling if you are currently unwell.

  • What happens during the test?

    It is a simple blood draw, often included as part of a broader cardiovascular risk panel alongside cholesterol testing.

  • How long do hs-CRP results take?

    Results are usually available within a few days.

  • What does a high hs-CRP result mean, and what happens next?

    A raised level may suggest increased cardiovascular risk, but it can also be elevated by recent infection, injury, or other inflammatory conditions unrelated to heart health, so it is often repeated to confirm a stable, chronic elevation before being factored into risk assessment. Your doctor will interpret this alongside your other risk factors.

  • Is the hs-CRP test accurate and reliable?

    It is a well-validated marker for chronic inflammation and is used in several established cardiovascular risk models, but because many things can raise CRP temporarily, a single result is less informative than a pattern confirmed over time or combined with other risk markers.

  • How much does private hs-CRP testing cost, and is it on the NHS?

    It can be requested on the NHS in certain circumstances, though it is more commonly included in private cardiovascular or general health screening panels, with results reviewed by a doctor; cost varies by provider.

  • How do I book hs-CRP testing privately, and how quickly can I be seen?

    Private clinics can typically arrange testing and a doctor's review within a few days, often alongside a broader heart health check.

  • Does lifestyle affect hs-CRP levels?

    Yes, factors such as smoking, obesity, lack of exercise, and poor sleep are all associated with higher CRP levels, so lifestyle changes may be part of the discussion if your result is raised.