How is your ANA titre calculated?

[Bonnie39]

I have blood results back and they just say "ANA Panel = positive"

[Wendy39]

Hello Bonnie39. I would like to know the answer to this question too. I had a positive test and then after 4 months of meds was told it was negative, (which the rheumy says what was expected). But I want to know my levels and can't understand why I was just told positive and negative.

[Whathappned]

Hi

I really don't have a clue on this subject but this is what I understand.

They titrate the blood. For example 1:40 is the blood sample mixed with 40 parts saline. It then goes 1:80, 1:160, 1:320, 1:640 etc. Labs vary in their standards for positive. Viruses can increase ANA and some people can have ANA without any disease.it needs to be used in conjunction with other bloods and symptoms and even then seems to be interpreted individually.

[Hidden]

Does ENA not measure titre rather than ANA? My ANA has given me different levels for different antibodies. E.g. anti-centromere >8 (filled my heart with joy when I read that!). I'm waiting for my ENA to hear different 'patterns' and titres. ENA = Extractable Nuclear Antigen, ANA = antinuclear antibodies Other than that it is as clear as mud to me!

[Whathappned in reply to Hidden]

I'm afraid my knowledge ended at the titrating with saline. After that I haven't a clue. I know some labs use different tests too. As far as specific ena and DNA etc - not a clue . I noticed that when I was shown my results by the nurse specialist my DNA was now 30 but the levels they used for normal range where different from the GP. Confused- oh yeh! X

[Bonnie39]

Gah! So frustrating struggling to understand this stuff!

[fabwheelie]

As Whathappened said for ANA they dilute the original sample into various titres and then test this diluted sample to see if it still shows positive. Something that shows positive at 1:640 is stronger positive than sample that is positive at 1:320 which is stronger positve than 1:160, 1:80 etc. A titre of 1:80 is usually considered negative / normal, as normal people without lupus can be positive for ANA upto this titre, but anything above 1:80 titre ususally indicates ANA positive sample

These links may help

thelupussite.com/ana.html -- for more detail

thelupussite.com/tests.html -- general info on SLE blood tests

labtestsonline.org.uk/map/a... - -click on the individual tests then the At a Glance , The Test tabs etc for each test eg see labtestsonline.org.uk/under...