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On Sufficient IgG Levels.


Senior Member
Midwest USA
There's been discussion on various threads about what constitutes "low" IgG levels and when it is appropriate to treat...I found this article illuminating on how the perspective has changed in the past decades.

What was considered sufficient 20 years ago in terms of IgG levels is no longer. Instead what is important is that the patient remain infection free.

I would encourage anyone with a history of chronic infections to have their IgG levels (total and subclasses) tested and pursue treatment with IgG if indicated. It can be a long and difficult process to find an immunologist that is properly trained in diagnosing immune deficiency (go figure!!) but can be very worthwhile in terms of treatment.

Dr Ballow stated that there are several recent studies that indicate that the best approach for dosing IVIg, or even SCIg, is on an individual basis. The goals are to treat the patient’s symptoms and their underlying problem. Furthermore, he revealed that the old standard of limiting the dose has been proved to be inadequate.

For example, “20 years ago or so we used this magic trough level, 500 mg/dL, as a number to shoot for. And we now realize that for many patients, a 500 mg/dL serum total IVIg level is not adequate. It’s not adequate to keep them infection free and it’s not adequate to keep them from getting chronic lung disease.

So, the push now by clinical immunologists is really to treat on an individual basis and dosing to keep the patient infection free, whether that may require a trough level of 500 mg/dL in some patients versus 750 mg/dL in other patients, or as much as 900 mg/dL in other patients.”

See more at: http://www.ajmc.com/journals/supple...se-of-immunoglobulin/P-3#sthash.Lp42jLod.dpuf

However, maintaining trough IgG levels above 500 mg/dl may not be sufficient to prevent infection in some patients. Notably, a 22-year follow-up of 90 patients with CVID found that a range of trough levels was necessary to prevent breakthrough bacterial infections (500-1700 mg/dl) and doses of replacement Ig required to prevent breakthrough bacterial infections ranged from 0.2 to 1.2 g/kg/month [26] . Results of a recent meta-analysis suggest that the incidence of pneumonia in patients with primary immunodeficiency progressively declines as trough levels increase up to at least 1000 mg/dl [27] . Therefore, it is important to identify and maintain the minimum serum IgG level that prevents infection within a patient's age-matched control range [28,29] . Plotting each patient's IgG levels over time against documented infections may help achieve this goal [29] .

Improved IgG3 Levels and Reduced Infection Rate in a Woman With CVID Switched From Intravenous to Subcutaneous Immunoglobulin Therapy
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Senior Member
Ontario, Canada

Do you have any thoughts on which tests might be the most reliable or accurate? There are several different ones available and I can't find any comparisons regarding what's different about them.


But I Look So Good.
Left Coast
I had low total and low subclasses 1 and 3.

And as some of you may know, I've been through 2 "allergists" to get a diagnosis and treatment. I call the "allergists" vs immunologist because their primary concern was asthma. One was too scared to use IVIG, the other, well he was willing, as long as I could prove my ME/CFS wasn't psychological. That went over well.

Try to find a clinical immunologist.