Product Description

The Anti-Streptolysin O (ASO) Titre blood test detects antibodies produced by the body in response to a streptococcal protein (Streptolysin O), which is released by Group A Streptococcus bacteria.

Purpose & Clinical Use

• Detecting Recent Streptococcal Infection: Confirms whether a recent strep infection (such as strep throat, scarlet fever, or a skin infection) occurred, even if the primary infection has cleared.

• Diagnosing Post-Streptococcal Complications: Used to evaluate symptoms of delayed immune complications that arise weeks after an untreated or partially treated strep infection, including:

  • Rheumatic Fever: Affects the heart, joints, skin, and central nervous system.

  • Post-Streptococcal Glomerulonephritis: A type of kidney inflammation.

Test Details

• Specimen: Standard blood draw (Serum).

• Preparation: No fasting or special preparation is required.

• Testing Dynamic: A single test shows current antibody levels. In many cases, paired tests (taken 10–14 days apart) are used to check if the antibody titre is rising, which indicates an active or very recent immune response.

Interpreting Results

• Normal / Low Titre: Indicates no recent Group A Streptococcus infection, or that antibody levels have naturally declined over time.

• Elevated / Rising Titre: Indicates a recent or ongoing immune response to Group A Streptococcus.

  • Note: An elevated ASO titre confirms a past strep infection, but it does not measure the severity of post-streptococcal complications; clinical diagnosis relies on symptoms and physical examination.