: Streptococcus pneumoniae Serotype 19A IgG Antibody, Serum, Mass Concentration

: What This Test Measures

: Streptococcus pneumoniae is a bacterium that can cause infections such as pneumonia, meningitis, and ear infections. Serotype 19A is one of many strains of this bacterium. IgG antibodies are proteins made by the immune system that recognize and help fight specific germs. This test measures how much IgG antibody against serotype 19A is present in the liquid part of your blood (serum).

: Why Your Doctor May Order It

: Your healthcare provider may order this test to check your immune response to pneumococcal bacteria, particularly after vaccination or when evaluating whether you may be at higher risk of pneumococcal infection. It can be part of an assessment of immune function in certain patients.

: How the Sample Is Collected

: A blood sample is drawn from a vein, usually in your arm, at a clinic or laboratory. The sample is then processed to separate the serum, which is the clear liquid portion, for testing.

: What the Results Mean

: Results are reported as a mass concentration of antibody in the serum. Your provider will interpret the level in the context of your vaccination history, symptoms, and overall health. Higher or lower values alone do not diagnose an infection; they are one piece of information among several.