After one month the rabbits were boosted and serum samples were collected every two weeks.

A serum sample for diphtheria toxoid antibodies was negative on day 7.

If the patient is from a non-endemic area, then diagnosis can be made from a single acute serum sample.

In the following experiments, five or six serum samples were used unless indicated otherwise.

Radioimmunoassay of coded serum samples was performed as described recently.

Get a serum sample from her as well.

Additional serum samples were taken in December 1990 from a randomly selected cohort of 141 people aged 40-65 years.

All 55 seropositive subjects from 1969 had serum samples taken in 1990 and 43/55 (78.2%) remained positive.

The serum samples were drawn at 8 weeks, and whole protein titers are shown in Figure 6.

Each group of four animals was immunized every two weeks, immediately after the removal of a serum sample.