clarify rubella titer please

[GingerSue]

here's my question

my textbook says that rubella titer of 1:8 is susceptible

then it says 1:10 indicates immunity

then it says 1:18 is immunity

so I ask at a local doctor's office and he says something vague about 25 or less than 50 (so I ask him to explain and he quickly says something about

micrograms per mole, then he says "the lab will indicate 'normal' and whether it needs to be given"

so I ask at the lab to see if she knows

and she says "it'll be negative or positive"

so I explain all these pieces of information

then she says that the results don't say "negative or positive"

does anybody know?

[TazziRN, RN]

Know what? I'm not sure what your question is?

[GingerSue]

what results indicate susceptibility

and what results indicate immunity

[crissrn27, RN]

We don't have just neg or pos we also have irr. which means it is the "in between" of immunity and non-immunity. We usually give the vax for this result. Sorry, can't think of the levels, though.

[GingerSue]

so it isn't a negative/positive result

and there is an irregular

my textbook says nothing about negative/positive/irregular for rubella titer

so I'm trying to clarify what to expect re: lab results

will they be negative/positive/irregular, or

will it say titer of 1:x

or will it say something about 25 or 50 (what is this 25 or 50?)

{when I have googled rubella titer - I find sites that say to give the vaccine at 1:8}

without the lab interpreting results,

how is a nurse to know how to interpret the blood work?

[labcat01, BSN, RN]

Correct me if i'm wrong anybody but I believe it will give you the titer level and then it will have a list of lab norms that say something like

Susceptibility

Immunity uncertain 1:8

Immune >1:8

The lab sheet should say what the guidelines are for immunity....at least that is MY understanding (but i'm a lowly student too!)

[Elvish, BSN, DNP, RN, NP]

Every lab I've ever worked with will have a numerical result followed by a pos/neg/equivocal interpretation. (Positive meaning, of course, rubella immunity.)

[sweetcheekers]

I've never seen the actual numbers used to determine the result, but we get a result listed as immune, equivocal, or non-immune. We vaccinate the equivocal and non-immune patients in our OB department before discharge.

[GingerSue]

thanks

does anyone understand about the 25 or 50 numbers in relation to rubella titer?

(I'm trying to understand what the doctor was talking about, he was from another country, so maybe he has been taught in a different system?

so I'm trying to understand in terms of the ratio, and in terms of what he was trying to explain)

[twickortweat]

just came across this by accident...it's pretty old but i thought maybe my input might help.

obtaining the titer through ratio indicates the sample was diluted e.g. 1:1 1 part serum 1 part diluent.

if the dilution at 1:10 gives a reactive result, it means that the level of the antibody in question is high enough to be considered positive. the higher the dilution with the positive reaction, the higher the level of the substance being measured. sometimes there is a formula to calculate for the value in units/volume for some substances.

that is actually the old way of determining titers not only for rubella but for other antibodies and other substances e.g. ketones as well generally speaking. these days our lab machines are more sophisticated and directly measure the amount of a particular substance in a specimen giving you an exact numerical value providing you with a nice reference range that does not confuse you.