Arthritis tests

is that normal crp 14

Q: Is CRP 14 mg/L a normal level if I’m having joint pain?


I’m having joint pain and the CRP test value is 14 mg/l. Is it a normal level?


The short answer is No, CRP value of 14 mg/l is not normal but it is not high enough to tell that you have ongoing chronic inflammation, but can tell that the inflammation is fading or weak infection or just a false value that is should be higher, and details are below…

If you test high-sensitive-CRP the normal level is up to 3, hence the 14 is 4 times higher than normal
but if the CRP test is done with the latex method the normal is up to 10, hence 14 is mildly elevated.

CRP levels will rise rapidly within the first 6 to 8 hours after the onset of acute infection and inflammations and CRP reading decrease quickly about 19 hours (a half-life) after initiation of a successful treatment course, and therefore it is a better helpful tool for bacterial infections and antibiotic treatments.

Another thing is that the CRP test may go up too much if there is a tissue inflammation flare-up like in rheumatoid arthritis flare-up.

What causes CRP levels to be slightly higher than normal without inflammation?

  1. Obesity
  2. Lack of exercise
  3. Cigarette smoking
  4. Diabetes

Because CRP is not specific to RA, some people with RA may have normal CRP levels, many other tests can predict the reasons for joint pain better than the general inflammatory markers like the CRP test, such joint pain tests may include:

  1. ACCP and RF tests: which used for investigation if the joint pain is due to rheumatoid arthritis disease.
  2. Sed Rate test: is a better indicator for chronic inflammatori episodes than CRP test.
  3. Uric acid test: which indicating how high is the uric acid in the bloodm which means their are too much uric acid in the blood that can deposit in the joints and cause inflammation and painful sensation, medically called Gout.
  4. Thyroid tests: to investigate if there is Hypothyroidism (underactive thyroid) which responsible for some kind of joint inflammation.
  5. ANA test: to predict if you have any sign of abnormal immunity behaviour or not?
  6. LE cells and dsDNA tests: used for predecting the lupus erythromatosus disease.

X-ray imaging is the first step for diagnosis of joint pain, and using the blood tests comes after that to complete, approve, or exclude the etiological causes.

What causes false-negative CRP levels?

What causes a mild increase in CRP levels while it should be higher?

Certain medicines can falsely cause CRP levels in the blood to be lower than normal or become lower than they should be. These include taking antibiotics, aspirin, steroids, and nonsteroidal anti-inflammatory drugs (NSAIDs) {which are widely used for relieving pain, reduce inflammation, and bring down a high temperature}.

Types of NSAIDs include:

  • ibuprofen.
  • naproxen.
  • diclofenac.
  • celecoxib.
  • mefenamic acid.
  • etoricoxib.
  • indomethacin.

What Test Shows Why knee Pain When Taking Thyroxine Pills?

Q: My mother takes thyroxine tablets but after many months she feels pain in her knees. how can I solve the reason for knee pain using medical tests?


Thyroxine tablets are the treatment for the under-active thyroid gland, a medical condition in which the thyroid gland secretions are lower than the healthy level, also called hypothyroidism in medical terms.

A simple diagram to illustrate how high TSH causes joint and knee pain
A simple diagram to illustrate how high TSH causes joint and knee pain

When the thyroid gland is under-active, the pituitary gland, also called the master gland, will release TSH hormone as normal feedback to stimulate the thyroid gland, and therefore the proteins deposit in the tissues excessively, because the thyroid gland is responsible for the management of proteins, thus these excessive precipitated proteins cause pain in joints and knees.

So that, the joint and knee pain when taking thyroxine-replacement-therapy is not due to the pills themselves, nevertheless, it is due to high TSH levels.


To know why you have joint and knee pain when on thyroxine treatment you may do thyroid function blood tests (TSH, FT4, and FT3), it might reveal that TSH level is high which can lead to precipitation of proteins and cause pain in joints and knee.

Negative RF Positive Anti-CCP Test, Rheumatoid or I am safe?

Anti-CCP antibodies in the blood are the most specific proteins for Rheumatoid Arthritis, So that clinical decision cannot neglect positive anti-ccp results when diagnosing RA disease.
Modern guidelines recommend for integration of Positive RF test and Positive Anti ccp test along with RA signs and symptoms to diagnose rheumatoid arthritis illness for sure.
But, sometimes a person has joint pain every morning and bone pain, etc, his’her doctor will recommend RF, Anti-ccp tests as an Rheumatoid preliminary panel, the person go to the laboratory to ensure that he or she doesn’t has Rheumatoid.
And surprise, RF test came negative which means no rheumatoid, and accp test cam positive, which means strong evidence of rheumatoid, the average person doesn’t know how medical decision is made for rheumatoid.
A.CCP antibodies are found exclusively in rheumatoid disease and rarely in other autoimmune conditions, such as lupus, Graves disease, Sjogren syndrome, and sometimes in tuberculosis infections, so that the ACCP result is a very strong sign of the onset of rheumatoid disease even if the RF test still not shown positive.
RF low accp high test result
Abstract from a study about diagnostic tests for rheumatoid arthritis including comparison of anti-cyclic citrullinated peptide antibodies, anti-keratin antibodies and IgM rheumatoid factors
The official link:

  • Objectives

. To examine the value of anti-cyclic citrullinated peptide (anti-CCP) antibodies,
anti-keratin antibodies (AKA) and immunoglobulin M rheumatoid factors (IgM RF) in
discriminating between rheumatoid arthritis (RA) and other rheumatic diseases, and to
determine whether the clinical manifestations or severity of erosions in RA are associated with
anti-CCP positivity.

  • Methods

. In a cross-sectional study, we determined the concentrations or titres of these three
markers in 179 RA patients and 50 controls. Erosions were quantified using the Larsen score in
129 patients.

  • Results

. Sensitivity was highest for IgM RF (75%), followed by anti-CCP antibodies (68%)
and AKA (46%). Specificity was highest for anti-CCP antibodies (96%), followed by AKA (94%)
and IgM RF (74%). A correlation with clinical manifestations and severity of erosions was
observed mainly for IgM RF positivity.

  • Conclusions
    . With their excellent specificity, anti-CCP antibodies can be useful in establishing
    the diagnosis of RA, but IgM RF is a better predictor of disease severity.

Related test results to RA diagnosis:

ASO Titer Explained

Previously we presented what is ASO titer meaning, and what to do when ASO titer go positive in blood results, this is to list the normal ASO titer and abnormal ASO titres that require more investigations, medical action and treatment.
Previous Elevated ASOT meaning
ASO is a medical term for “antistreptolysin O”, antistreptolysin O is a medical term for “ASO antibody” or “ASO Ab”, which is a weapon released against foreign attacks by a substance called “streptolysin O”, streptolysin O is a bacterial toxin breaks blood cells and causes hydrolysis of your blood, complications of high ASO titers include kidney inflammation, arthritis, rheumatic fever which scars the valves of the heart.
Strep‘ is a shortcut for Streptococcus bacteria
Titer or titre means “concentration” or “unit”
Normal ASO titer range  is 100 IU/mL for adult and preschool age child, 200 IU/mL for child at school age
It’s better to call it negative level than normal level.
ASO test is a measure of the antistreptolysin O antibodies level in your blood,
When ASOT blood test results show:
A value from 0.0 to 250 unit/ml it means probably no strep infection, ASO titer from 250 to 400 titer/ml means equivocal result need a confirmation by serial testing, ASO titer higher than 400 titer/ml means probable recent strep infection.
asot chart
ASO test are used when searching for evidence of recent streptococcal infection in suspected post-streptococcal glomerulonephritis (PSGN) ” a kidney inflammation disease” or rheumatic fever (RF).
Serial ASOT tests should be done, looking for rising titers.
A high ASO level is more likely to be significant and sustained ASO levels may indicate persisting infection. PSGN or RF can easily be over-diagnosed when an isolated, equivocal, titre is used as evidence.
See more ASOT results interpretation:
7 years daughter had ASO titre over 1000 and knee pain
ASOT Titre 800 and CRP 30
Confirmation Tests after High ASO Titer:
Time-course after streptococcal infection ASOT and ASK start to rise a few days after infection commences. ADNAse tends to rise somewhat later. In uncomplicated infections, ASOT does not usually rise in streptococcal skin infections whereas ADNAse does.
How long time does ASO titer take to be normal again?
ASO titres return to baseline levels in 23 months. Average ASO baseline levels in adults are half those in children due to the frequent streptococcal throat infections in the latter.