Why is SPS (sodium polyanetholesulfonate) recommended for use in blood cultures?

Sodium polyanetholesulfonate (SPS) is specifically recommended for use in blood cultures primarily because it does not inhibit bacterial growth. This characteristic is crucial for the accurate identification of bacterial pathogens in a blood sample. Blood cultures are designed to detect the presence of bacteria in the bloodstream, and the presence of any substance that could inhibit bacterial growth would interfere with the test's effectiveness.

SPS acts as an anticoagulant, preventing clot formation, which is essential for ensuring that bacteria remain suspended in the blood sample, allowing them to be cultured and identified. By not inhibiting bacterial growth, SPS facilitates the growth of microorganisms that may be present in low numbers, enabling a precise diagnosis of infections.

While it does support the prevention of clotting, since blood cultures need to maintain the viability of potential pathogens for accurate results, the primary reason for its use is the ability to allow bacteria to grow unimpeded in the culture environment. This distinction is key in understanding the role of SPS in the context of blood culture procedures and microbiology.