What is RA Titer?
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?
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.
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:
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.
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
How Is Rheumatoid Factor Measured?
The amount of rheumatoid factor in blood can be measured by:
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.
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:
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. I hope this helps to sort out the "titre" vs "factor" question.
K.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.