The two columns on the left show negative and positive immunoblot results for a particular pathogen. The numbered columns are blots of samples from 11 patients. Which patients are most likely uninfected?

Verified step by step guidance

1. Understand that an immunoblot (Western blot) test detects specific antibodies in patient samples that bind to pathogen proteins, indicating infection.
2. Identify the pattern of bands in the negative control column, which shows no bands or only nonspecific bands, representing uninfected samples.
3. Identify the pattern of bands in the positive control column, which shows specific bands corresponding to pathogen proteins, representing infected samples.
4. Compare each patient's blot (columns 1 to 11) to the positive and negative controls to see if their banding pattern matches the positive control (indicating infection) or the negative control (indicating no infection).
5. Patients whose blot patterns closely resemble the negative control (lack of specific bands seen in the positive control) are most likely uninfected.

Key Concepts

Immunoblot (Western Blot) Technique

Immunoblotting is a laboratory method used to detect specific proteins in a sample by using antibodies. It separates proteins by size via gel electrophoresis, transfers them to a membrane, and then probes with antibodies to identify target antigens, indicating presence of infection.

Interpretation of Positive and Negative Immunoblot Results

A positive immunoblot shows distinct bands corresponding to pathogen-specific proteins, indicating infection or exposure. A negative result lacks these bands, suggesting absence of infection. Comparing patient samples to known positive and negative controls helps determine infection status.

Serological Diagnosis of Infection

Serological tests detect antibodies or antigens in patient samples to diagnose infections. Presence of antibodies against pathogen proteins in immunoblots reflects immune response, while absence suggests no infection or early stage before antibody production.