Ig titers; are there standards?

Yjgent yjgent at aol.com
Sat Jul 22 10:56:14 EST 2000

>  Are there any standards for interpreting Ig levels? Any tables to
>convert results obtained with test Y to the corresponding results in test

This is trying to compare apples and oranges. A proper diagnosis of a rising
titer should be accomplished by testing 2 samples (taken 2 - 4 weeks apart) and
tested at the same time with the same kit (same lot#, controls, reagents).

A 4 fold increase in titer indicates an infection. The IGM will show first,
followed by the IGG. Usually the IGM will peak and then drop off early while
the IGG will peak and stay high for a long time. If an "acute" sample cannot be
drawn and only a convelescent one is tested the test kits will have a single
level over which will indicate a current or past infection.

A positive IGM (high titer or 4 fold increase) indicates new current infection.

A positive IGG (high titer or 4 fold increase) with a positive IGM indicates a
current infection in the early stage.

A positive IGG (high titer or 4 fold increase) with a negative IGM indicates a
current infection in the later stages OR a past infection that may have

I have had many conversations with doctors who just can't get this stuff and
have a hard time understanding it. Sometimes I just have to tell them to
contact an infectious diseas doc.

John Gentile M(ASCP)                   President - Rhode Island Apple Group
yjgent at aol.com
Microbiologists do it with culture.

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