Method for Determining Derivatized Analytes in A Separated Biological Fluid

A method for determining the presence, concentration, or amount of secosteroids of interest in a blood sample comprising the steps of:

• a. collecting whole blood;
• b. separating a plasma sample from said whole blood sample;
• c. aliquoting said plasma sample;
• d. derivatizing secosteroids within said plasma sample using a derivatizing agent;
• e. transferring said sample to a preparation vessel;
• f. purifying said sample;
• and
• g. analyzing desired components of said sample.

A method for determining the presence, concentration, or amount of Vitamin D in a blood sample comprising the steps of:

• a. collecting whole blood;
• b. separating a plasma sample from said whole blood sample;
• c. aliquoting said plasma sample;
• d. derivatizing Vitamin D within said plasma sample using a derivatizing agent;
• e. transferring said sample to a preparation vessel;
• f. purifying said sample;
• and
• g. analyzing desired components of said sample.

A method for determining the presence, concentration, or amount of analytes of interest in a plasma sample comprising the steps of:

• a. Collecting, separating, and aliquoting a plasma sample by use of a PSD, wherein said collection reservoir of said PSD comprises an absorptive material element and said aliquoted plasma sample becomes substantially absorbed by said absorptive material element;
• b. Preparing said plasma sample for analysis;
• c. Purifying said plasma sample;
• and
• d. Analyzing said plasma sample.

A method for determining the presence, concentration, or amount of Vitamin D and its analogs in a plasma sample comprising the steps of:

• a. Collecting, separating, and aliquoting a plasma sample by use of a PSD, wherein said collection reservoir of said PSD comprises an absorptive material element and said aliquoted plasma sample becomes substantially absorbed by said absorptive material element;
• b. Preparing said plasma sample for analysis;
• c. Purifying said plasma sample;
• and
• d. Analyzing said plasma sample.