American Pharmaceutical said the drug's endotoxin levels were within allowable limits.

Because endotoxin molecular weight may vary a great deal (10,000 to 1,000,000 Da), endotoxin levels are measured in "endotoxin units" (EU).

The FDA has set the following maximum permissible endotoxin levels for drugs distributed in the United States:

But perhaps the biggest drawback of this test was its inability to quantify the endotoxin level.

Although endotoxins are relatively thermally stable, sufficient heating (250 C for 30 min) results in a 3log reduction of endotoxin levels.

Based on primary packaging material as syringes or vials, a glass temperature of 250 C and a holding time of 30 minutes is typical to achieve a reduction of endotoxin levels by a factor of 1000.

However, recent studies on airborne endotoxin found that the presence of cats had no effect, and that there were significantly lower endotoxin levels in houses with cats compared to dogs.

The investigators were able to establish a strong association between endotoxin levels in mattress dust and rates of allergic and autoimmune conditions.

In the study, farms did have higher endotoxin levels than nonfarm homes, and the scientists found that in mattresses, the highest levels of endotoxin were associated with the lowest risk of asthma and allergy.

The study showed only correlations between endotoxin levels and allergy; it did not prove cause and effect.