Medical Laboratory Scientist (MLS) ASCP Exam 2025 – 400 Free Practice Questions to Pass the Exam

The correct choice demonstrates the specific serological tests used to identify previous infections caused by Streptococcus bacteria, particularly Streptococcus pyogenes, which can lead to conditions such as pharyngitis or skin infections like impetigo.

The ASO (Anti-Streptolysin O) titer measures antibodies produced in response to streptolysin O, a toxin released by Streptococcus pyogenes. An elevated ASO level indicates a recent streptococcal infection. Similarly, the Anti-DNase B test detects antibodies against the DNase B enzyme produced by the bacteria. A positive result signifies a prior infection, often related to skin conditions such as impetigo.

Both of these tests are serological markers that can provide evidence of previous Streptococcal infections, making them essential for diagnosing potential complications like rheumatic fever or post-streptococcal glomerulonephritis that may arise from untreated infections.

In contrast, other tests listed do not specifically relate to prior Streptococcal infections. C-reactive protein and complete blood count assess general inflammation and infection rather than targeting streptococcal infections directly. The rapid antigen test and throat culture are focused on identifying active infections,