Which laboratory investigations are essential for the diagnosis and management of neutropenic sepsis?

Essential laboratory investigations for the diagnosis and management of neutropenic sepsis include:

• Blood cultures, ideally taken before antibiotic administration, to identify primary bacteraemia and guide targeted therapy.
• Full blood count (FBC) to assess neutrophil count (confirming neutropenia), white cell count, and thrombocytopenia which may indicate disseminated intravascular coagulation (DIC).
• Blood gas analysis including glucose and lactate measurement, as lactate is a marker of illness severity and cellular stress.
• C-reactive protein (CRP) to indicate infection and/or inflammation.
• Kidney function tests (creatinine, urea, and electrolytes) to detect dehydration or acute kidney injury.
• Liver function tests (including bilirubin and alanine aminotransferase) to assess for liver dysfunction or chemotherapy-induced liver injury.
• Clotting screen to detect coagulopathy or DIC.
• Urine analysis and culture, especially in children under 5 years, to identify urinary sources of infection.
• Sputum microscopy and culture if respiratory infection is suspected.

Additional investigations such as chest X-ray should be performed only if clinically indicated to identify the source of infection.

These investigations support early diagnosis, risk stratification, and guide empiric and targeted antibiotic therapy as well as monitoring response to treatment in neutropenic sepsis.

References: ¹,²,³,⁴