Q. A 32-year-old woman comes to your clinic with complaints of malaise and general fatigue. She reports that she has been feeling unwell for several weeks and is concerned that she may have contracted HIV. She admits to having multiple sexual partners in the past, and she has not been using protection consistently. She also reports having a recent flu-like illness, including fever, headache, and body aches. On physical examination, the patient appears pale and fatigued. She has no fever, but her lymph nodes are enlarged, especially in her neck and groin. You order blood tests, including an HIV test. The initial screening test is positive, so you order a western blot analysis to confirm the diagnosis. The western blot analysis is performed using her serum sample and demonstrates the presence of antibodies against p24, p31, and gp41, confirming the diagnosis of HIV infection. Which of the following is NOT a step in western blot analysis?