Who is at High Risk for Sepsis?

While anyone can develop sepsis if they have an infection, the following groups are at significantly higher risk and require extra caution:

1. Infants and the Elderly: A common characteristic of these individuals is an underdeveloped immune system. The immune systems of infants and young children are not yet fully developed, while the immune systems of the elderly decline with age and are often accompanied by multiple underlying diseases, making it difficult for them to effectively fight infections.
2. Patients with Chronic Diseases: Patients with diseases such as diabetes, cancer, liver and kidney disease, chronic obstructive pulmonary disease (COPD) or HIV/AIDS have weaker body defense mechanisms and organ functions, making infections more likely to get out of control.
3. Immunocompromised Individuals: These include cancer patients undergoing chemotherapy, people taking immunosuppressants after an organ transplant, and people with autoimmune diseases, in which their immune systems are unable to respond effectively to pathogens.
4. Patients with Severe Trauma or Major Surgery: For patients with extensive burns, severe trauma or major surgical operations, the skin or mucosal barrier is destroyed, providing a channel for pathogens to invade, and the body is in a state of high stress.
5. Users of Invasive Medical Devices: Patients with catheters (such as central venous catheters, urinary catheters), using ventilators or having drainage tubes in their bodies, these devices may become “shortcuts” for pathogens to enter the human body.
6. Individuals with Recent Infections or Hospitalizations: Especially for patients with pneumonia, abdominal infection, urinary tract infection or skin infection, if the treatment is not timely or ineffective, the infection can easily spread to the blood and cause sepsis.

How to detect sepsis? Key detection reagents play a central role

If high-risk individuals develop suspected symptoms of infection (such as fever, chills, shortness of breath, rapid heart rate, and confusion), they should seek medical attention immediately. Early diagnosis relies on a series of clinical assessments and laboratory tests, among which a variety of in vitro diagnostic (IVD) test reagents are the indispensable “eyes” of clinicians.

1. Microbial Culture (Blood Culture) – The Diagnostic “Gold Standard”
   • Method: Samples of the patient’s blood, urine, sputum, or other suspected sites of infection are collected and placed in bottles containing culture medium, which are then incubated to encourage the growth of pathogens (bacteria or fungi).
   • Role: This is the “gold standard” for confirming sepsis and identifying the causative pathogen. Once a pathogen is cultured, antimicrobial susceptibility testing (AST) can be performed to guide doctors in selecting the most effective antibiotics. However, its main drawback is the time required (typically 24-72 hours for results), which is not conducive to initial emergency decision-making.
2. Biomarker Testing – Rapid “Alarm Systems”
   In order to make up for the time-consuming defect of culture, a variety of biomarker detection reagents are widely used for rapid auxiliary diagnosis.
   • Procalcitonin (PCT) testing: This is currently the most important and specific biomarker associated with sepsis. PCT is a protein present at very low levels in healthy individuals, but is produced in large quantities in multiple tissues throughout the body during severe bacterial infection. PCT assays (usually using immunochromatographic or chemiluminescent methods) provide quantitative results within 1-2 hours. Elevated PCT levels are highly suggestive of bacterial sepsis and can be used to monitor the effectiveness of antibiotic therapy and guide discontinuation.
   • C-reactive protein (CRP) testing: CRP is an acute-phase protein that rapidly increases in response to inflammation or infection. While highly sensitive, it is less specific than PCT because it can be elevated in a variety of conditions, including viral infections and trauma. It is often used in conjunction with other markers.
   • White Blood Cell Count (WBC) and Neutrophil Percentage: This is the most basic complete blood count (CBC) test. Sepsis patients often exhibit a significant increase or decrease in WBC and an increased percentage of neutrophils (a left shift). However, its specificity is low, and it must be interpreted alongside other indicators.
3. Molecular Diagnostic Techniques – Precision “Scouts”
   • Method: Techniques such as Polymerase Chain Reaction (PCR) and Metagenomic Next-Generation Sequencing (mNGS). These technologies use specific primers and probes (which can be seen as advanced “reagents”) to directly detect pathogen nucleic acids (DNA or RNA).
   • Role: They do not require culture and can rapidly identify pathogens in the blood within hours, even detecting organisms that are difficult to culture. Particularly when traditional cultures are negative but clinical suspicion remains high, mNGS can provide critical diagnostic clues. However, these methods are more expensive and do not provide antibiotic susceptibility information.
4. Lactate Testing – Measuring the “Crisis” Level
   • Tissue hypoperfusion and hypoxia are central to sepsis-induced organ failure. Elevated lactate levels are a clear marker of tissue hypoxia. Bedside rapid lactate test kits can rapidly measure plasma lactate concentrations (within minutes). Hyperlactatemia (>2 mmol/L) strongly indicates severe illness and a poor prognosis, and is an important indicator for initiating intensive treatment.

Conclusion

Sepsis is a race against time. The elderly, the frail, those with underlying medical conditions, and those with specific medical conditions are primary targets. For these high-risk groups, any signs of infection should be treated with caution. Modern medicine has established a rapid diagnostic system through a range of methods, including blood cultures, biomarker testing such as PCT/CRP, molecular diagnostics, and lactate testing. Among these, a variety of highly efficient and sensitive detection reagents are the cornerstones of early warning, accurate identification, and timely intervention, greatly improving patients’ chances of survival. Recognizing risks, addressing early symptoms, and relying on advanced detection technologies are our most powerful weapons against this “invisible killer.”