CRP and Sedimentation Rate: What Raised Values Mean
CRP and the sedimentation rate are the two most common “inflammation” tests and are almost always ordered together, even though they measure different things at different speeds. CRP reacts within a few hours and drops back to normal quickly, the sedimentation rate rises slowly and falls slowly. That is why a report in which one is raised and the other is normal is not an error but information. This article covers the normal values, what the different CRP levels mean, the most common causes of a raised sedimentation rate and when a report calls for an appointment.
Normal values for CRP and the sedimentation rate
| Test | Reference values | Note |
|---|---|---|
| CRP (C-reactive protein) | up to 5 mg/L (some laboratories up to 3 or up to 10) | Rises 6 to 8 hours after inflammation begins, peaks within 2 days, falls within a few days of recovery. |
| hs-CRP (high sensitivity) | below 1 low, 1 to 3 average, above 3 mg/L raised cardiovascular risk | Run in healthy people with no infection, as an estimate of heart risk, not as a test for inflammation. |
| Sedimentation rate (ESR), men | up to 15 mm/h below the age of 50; up to 20 mm/h after 50 | Measures how quickly red cells sink in a tube over one hour. |
| Sedimentation rate (ESR), women | up to 20 mm/h below the age of 50; up to 30 mm/h after 50 | Physiologically higher in women, in pregnancy and with age. |
What the CRP levels mean
| CRP | What usually lies behind it |
|---|---|
| 5 to 10 mg/L | Mildly raised: a cold, a mild viral infection, the teeth, obesity, smoking, a hard workout, a recent vaccination. On its own it rarely calls for anything beyond a recheck. |
| 10 to 40 mg/L | Moderate: most viral infections, milder bacterial ones, active autoimmune disease, recovery after surgery. |
| 40 to 100 mg/L | A bacterial infection is more likely (tonsillitis, pneumonia, a urinary infection, skin infections) or stronger inflammation; the doctor looks for the cause, not just a recheck. |
| above 100 mg/L | Severe bacterial infection, sepsis, extensive inflammation, trauma or burns. This goes to a doctor at once, not in a few days. |
The most common question a report raises: CRP raised but white cells normal. That is usual in viral infections and at the very start of an illness, because CRP reacts faster than the blood count. The other way round, high white cells with a normal CRP are seen with stress, corticosteroids and smoking. Neither is an alarm in itself. What is: a CRP that does not fall after treatment has finished, or one that rises without a single symptom of infection, because that is when a doctor starts looking for hidden inflammation.
A raised sedimentation rate: why it so often has no obvious cause
The sedimentation rate depends on the proteins in the plasma, so it rises with everything that changes them: infections, autoimmune diseases, but also anemia, pregnancy, kidney disease, obesity and older age. That is why “a sedimentation rate of 30 in a woman” over fifty is most often a normal result, while the same value in a young man deserves attention. The sedimentation rate also stays raised for weeks after an infection has passed, long after the CRP has returned to normal.
Values above 50 mm/h, and especially above 100, rarely have no cause and call for an appointment: rheumatic diseases, chronic infections, kidney disease, and in older people disorders of the blood proteins that are found by electrophoresis. The sedimentation rate is also the main test for following some rheumatic conditions, which is why a rheumatologist repeats it at check-ups.
When one is raised and the other is not
- CRP raised, sedimentation rate normal: fresh inflammation, the first days of an infection. The sedimentation rate has not had time to climb yet.
- Sedimentation rate raised, CRP normal: the tail of an infection that has passed, anemia, pregnancy, age, or a chronic condition with low activity. In some autoimmune diseases, lupus for example, the CRP stays low even while the disease is active.
- Both high: active inflammation or an infection that is ongoing; the doctor looks for the source.
How “a raised CRP” is treated
You do not treat a number, you treat the cause. CRP is a measure, not a disease, and there is no medicine “for CRP”. If the cause is a bacterial infection, it falls after antibiotics; if it is a virus, it falls by itself; if it is an autoimmune disease, it falls once that is brought under control. With a chronically mildly raised CRP and no infection, the doctor looks at weight, smoking, blood sugar, lipids and the teeth, because those are quiet sources of inflammation you do not feel.
What an appointment at Miren Medic looks like
With a CRP and sedimentation report that worries you, the first step is an appointment with an internist or a general practitioner: a conversation about your symptoms, an examination, and if needed a blood count, urine, liver and kidneys from the same sample. If the picture points to the joints and connective tissue, a rheumatologist follows; if it points to the blood cell lines, a hematologist. At the Miren Medic clinic all three services work without a referral, and the tests are run in the clinic laboratory, so the recheck and the interpretation can be done in a single visit.
Prices
| Service | Price |
|---|---|
| Internal medicine appointment (Dr Andreja Kovačević) | 6.000 RSD |
| General practitioner appointment | 4.000 RSD |
| Rheumatology appointment (Dr Marko Vorkapić) | 6.000 RSD |
| Hematology appointment (Assist. Prof. Dr Danijela Leković) | 12.000 RSD |
Frequently asked questions
What are normal CRP values?
Up to 5 mg/L in most laboratories, and some use a cut-off of 3 or 10 mg/L. Values of 5 to 10 are mildly raised, 10 to 40 moderate, 40 to 100 point to a bacterial infection or stronger inflammation, and above 100 to a serious condition that needs an urgent appointment.
What does a raised CRP with normal white cells mean?
Most often a viral infection or the very beginning of an illness, because CRP reacts faster than the blood count. It is not an alarm in itself; what matters is that the CRP falls after recovery and that no symptoms persist.
What are normal sedimentation rate values in women?
Up to 20 mm/h below the age of 50 and up to 30 mm/h after that. The sedimentation rate is physiologically higher in women, in pregnancy and with age, so a value of 25 or 30 in a woman over fifty is most often not a result that calls for treatment.
Why is the sedimentation rate raised while the CRP is normal?
Because the sedimentation rate takes weeks to fall after an infection, and it also rises with anemia, pregnancy and older age. If it is very high with no explanation, the doctor checks for rheumatic diseases, the kidneys and the blood proteins.
How is a raised CRP treated?
There is no medicine for CRP; the cause is what gets treated. With a bacterial infection it falls on antibiotics, with a virus by itself, with an autoimmune disease once that is under control. A chronically mildly raised CRP with no infection points to weight, smoking, blood sugar, lipids or the teeth.
When should you see a doctor about a CRP and sedimentation report?
When the CRP is above 40 mg/L or the sedimentation rate above 50 mm/h, when the result does not fall after treatment, when it rises with no symptoms of infection, or when it comes with a temperature that persists, weight loss, night sweats or joint pain.
Book an appointment
If your CRP or sedimentation rate is raised and you do not know why, book an appointment with an internist at the Miren Medic clinic. The examination, the follow-up tests and the interpretation come from one place, without a referral, and if needed a referral on to a rheumatologist or hematologist within the same clinic.
