What is RA Titer? | Arthritis Information


I asked this once before on a related thread but had no luck with an answer so I'm trying a dedicated thread for my question.  I've looked it up on the internet but I'm still not clear on what it is.  For instance, I have a positive result for RF but there was no number next to it.  Then the next page said RA titer is 160 IU/ML.  Is that the number that says how high the RF is?  I've been able to figure out the ANA, ANCA, CCP, etc. pretty much by looking it up, but this RA titer thing has me stumped.  I'd like to know how high the RF is but don't see a number anywhere else that would explain it.  Thanks for any information you can provide.  I think to be sure you should just call your doctors office.  The nurses are usually great at answering any and all questions, even if they have to research and get back to you.

Now that said, my lab does list the RF in that manner.  Mine looks like this
RA rhuematoid     173.8/ML      HIGH        Normal range <0.0-13.0 IU/m>
OK, maybe titer is the actual measurement of how high the RF is, based on what your labs look like. Mine doesn't give a range, just that the RF is positive.  I'll see what others here say too and if I'm still not sure, I'll ask the nurse at my next visit, in about a month.   Thanks TheLa!No problem.  Since your number is pretty high, I'm surprised they still have you as undifferentiated connective disease.  Did they do more labs that are a little more specific?  My rhuemy did the CCP test after the rf was so high.  The CCP is a test that is more conclusive and specific to RA. 
EDIT: sorry I see you mentioned the CCP-what was it?
TheLa2008-03-18 15:27:06The Anti-CCP was marked as high at 5.00 but I think it's just barely high because the range is below 4.90.  But I don't really know if those 10 points means it's barely high or not.  The SED rate was normal at 8 with a range of 0-30.  And a PTT (LAC) screen (for lupus?) was high at 41, but 40 is the upper limit so again, just barely over normal, I guess.  I think the RD considers it undifferentiated because I didn't have a lot of fatigue, (just muscle weakness) or any swelling.  I had some joint pain and muscles spasms that moved around and didn't have a pattern on both sides.  And that scary neuropathy too.  Apparently he thought it conclusive enough to treat but there are some days I'd really like to have a more difinitive diagnosis.  Not that I want full-blown RA or lupus, but I like things in black and white.  This gray area stuff is unsettling to me.  Jesse882008-03-18 16:40:54I'm with ya on the definitive diagnosis need.  I have said many times that I'm just as glad my numbers are so high because there was no doubt.  My CCP was 181.
I'm confused that they marked the CCP as high.  My labs are pretty detailed, and they have Less than 20 as negative
20-39 weak positive
40-59 moderate positive
60 or greater strong positive.  Actually, your titer is normal.  See below:

Definition    Return to top

RF is an antibody that attaches to a substance in the body called immunoglobulin G (IgG), forming a molecule known as an immune complex. The immune complex can trigger different types of inflammation-related processes in the body.

This article discusses the test to detect and measure the level of RF in the blood.

How the Test is Performed    Return to top

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

How to Prepare for the Test    Return to top

No special preparation is usually necessary.

How the Test Will Feel    Return to top

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the Test is Performed    Return to top

This test is most often used to diagnose rheumatoid arthritis. About 80% of patients with rheumatoid arthritis have positive RF tests.

It may also be used to rule out or diagnose other inflammation-related conditions.

Normal Results    Return to top

Normal values depend on what method the laboratory uses to detect and measure the RF. Some examples are below:

  • Less than 60 u/mL (with the nephelometric method)
  • Less than 1:80 titer (with the agglutination method)

What Abnormal Results Mean    Return to top

A positive test may be due to:

Additional conditions under which the test may be performed:

Risks    Return to top

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks:

  • Excessive bleeding
  • Fainting or feeling lightheaded
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)

Considerations    Return to top

The RF test can be positive in some healthy people.

Update Date: 5/27/2007

Updated by: Steve Lee, DO, Rheumatology Fellow, Loma Linda University Medical Center, Loma Linda, CA. Review provided by VeriMed Healthcare Network
Phat girl- are you saying the distinction with Jesse is the word titer?  Because she didn't write it as a ratio 1:60 she wrote it as 160.  A difference of the two methods described above?  (nephelometric vs. agglutination) Is using the word titer important?  Because also remember her lab did say it was positive so to me it still looks like 160 then, a high positive in the nephelometric method. Her post says her titer is 160.  That's what I based my post on.
PhatsDid you understand my questions though?  I'm confused.  Well, I thought so, but maybe not.  The positive RF is different from the titer.  Is that what you are asking?  I'm trying to find more info on the web.
Maybe this will help???

How Is Rheumatoid Factor Measured?

The amount of rheumatoid factor in blood can be measured by:

Agglutination tests

One method mixes the patient's blood with tiny latex beads covered with human antibodies (IgG). The latex beads clump or agglutinate if rheumatoid factor (IgM RF) is present. Another method mixes the patient's blood with sheep red blood cells that have been covered with rabbit antibodies. The red blood cells clump if rheumatoid factor is present.

A titer is an indicator of how much the agglutination test blood sample can be diluted before rheumatoid factor is undetectable. A titer of 1:20 indicates that rheumatoid factor can be detected when 1 part of blood is diluted by up to 20 parts saline. The lab value for rheumatoid factor of 1:20 or less is considered normal.

Nephlometry test

This method mixes the patient's blood with antibodies that cause the blood to clump if rheumatoid factor is present. A light is passed through the tube containing the mixture and an instrument measures how much light is blocked by the mixture. Higher levels of rheumatoid factor create a more cloudy sample and allow less light to pass through, measured in units. The lab value for rheumatoid factor of 23 or less units is considered normal.

When analyzing lab results the following should be considered:

  • A rheumatoid factor more than 23 units and a titer more than 1:80 is indicative of rheumatoid arthritis but may also occur in other conditions.
  • False positive results can occur when the blood is high in fats.
  • Inaccurate results can be caused by improper handling of the blood specimen.
  • A negative test result for rheumatoid factor does not exclude the diagnosis of rheumatoid arthritis.
No not quite.  She was after what was the RF. 
My rf is printed   RA RHUEMATOID 173.8 IU/ML  which is high- true it doesn't use the word titer, but she was asking if that test referred to her RF.  She already knows it's high.  I was confirming that my lab writes it as RA not RF.
The only thing I can think of is she meant to type 1:60 instead of 160, but her labs say RF positive.  She is just after her number.
Edit-Jesse you probably would be wise to check with your doctors office like I originally said.  Hopefully you picked up some interesting info on this thread nonetheless.

A titre is a measurement of the amount or concentration of a substance in a solution.  It usually refers to the amount of medicine or antibodies found in a patient's blood.

Results can be reported in titres (normal < 1:20) but more commonly as units and <23u is normal (normal levels may vary from laboratory to laboratory). The sensitivity and specificity of rheumatoid factor for rheumatoid disease is low and thus it is not a good screening test. However, the predictive value of rheumatoid factor in patients with symmetric polyarticular joint swelling is 80%.
I plagiarized the above from two of my 2000 medical/RA study sites.
Thanks everyone.  I guess I still have to ask the doctor on my next visit.  The number is in fact 160, not 1:60 and even reading all of the above, as well as my own research, I still can't determine exactly if that 160 is the level of the positive RF.  Sorry, I know I must sound a little dense on this.  I just can't make sense of this particular test.  I started thinking about it again because people here often refer to the number of their RF and I never knew what mine was.  I suspected it was the titer number because they do follow up tests on anything that comes out positive and the titer was the next test after the positive RF.  Why don't they make these tests uniform so they're easier to understand?  Oh well, I'll found out next RD visit.  I'll save the phone calls between visits for medicine related questions.  I appreciate the effort you've all taken to help me out with this. 
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