From the Guidelines
Diagnosing Central Line-associated Bloodstream Infections (CLABSI) from a Peripherally Inserted Central Catheter (PICC) line versus a Port requires a combination of clinical manifestations and microbiological results. To diagnose CLABSI, clinicians should look for signs of infection such as tenderness, pain, induration, and drainage at the catheter site, as well as systemic signs of infection like hypotension, chills, and fever 1.
Diagnostic Criteria
The diagnosis of CLABSI is considered when there are no other sources of bacteremia and a central venous catheter (CVC) has been in place for more than 2 days 1. The following diagnostic criteria can be used:
- Paired blood cultures: Obtain paired blood samples from the catheter and a peripheral vein, with the same volume of blood, to compare the colony counts of the same organism 1, 2.
- Quantitative blood cultures: A ratio of ≥3:1 (catheter hub/tip vs peripheral) is indicative of CLABSI 1, 3.
- Differential time to positivity (DTP): Growth from the catheter hub at least 2 hours before growth detected from the peripheral vein sample is suggestive of CLABSI 1, 4.
- Catheter culture: Semi-quantitative or quantitative culture of the catheter tip or hub can be used to diagnose CLABSI, with >15 CFU/catheter segment or >10^2 CFU/catheter segment, respectively 1, 3, 4.
Specific Considerations for PICC Lines and Ports
When diagnosing CLABSI in patients with PICC lines or ports, it is essential to consider the type of catheter and the clinical presentation. For example, tunnel infections are more common in tunneled catheters like PICC lines, and are characterized by tenderness, erythema, and induration along the subcutaneous tract of the catheter 5, 4. In contrast, pocket infections are more common in ports, and are characterized by infected fluid in the subcutaneous pocket of the device 4.
Clinical Practice Guidelines
The diagnosis and management of CLABSI should be guided by clinical practice guidelines, such as those published by the Infectious Diseases Society of America (IDSA) 4 and the Kidney Disease Outcomes Quality Initiative (KDOQI) 3. These guidelines provide recommendations for the diagnosis, treatment, and prevention of CLABSI, and emphasize the importance of a multidisciplinary approach to managing these infections 5.
By following these diagnostic criteria and guidelines, clinicians can accurately diagnose CLABSI and provide effective treatment to prevent complications and improve patient outcomes.
From the Research
Diagnosing Central Line-Associated Bloodstream Infections (CLABSIs)
To diagnose if bacteremia is due to a Central Line-associated bloodstream infection (CLABSI) from a Peripherally Inserted Central Catheter (PICC) line versus a Port, several methods can be employed:
- Comparative quantitative culture of blood obtained via the Central Venous Catheter (CVC) and a peripheral vein (PV) is a well-accepted method of diagnosing CRBI 6.
- Differential time to positivity has demonstrated marked accuracy and practicality as it allows the catheter to remain in place 7.
- In patients with a double lumen CVC, CRBI can be diagnosed by a > or = 5-fold difference in colony-forming units/mL between the 2 lumens with sensitivity, specificity, PPV and likelihood ratio of 61.8, 93.3, 92.2 and 9.22, respectively 6.
- In patients with a single or double lumen CVC, CRBI can be diagnosed when the CVC culture yields > or = 100 colony-forming units/mL with sensitivity, specificity, PPV and likelihood ratio of 75.5, 69.1, 79.3, and 2.44, respectively 6.
Predictors of CLABSIs
Several predictors of CLABSIs have been identified, including:
- Antibiotic usage within the previous week, with an odds ratio (OR) of 4.89 [95% confidence interval (CI): 1.67, 14.35] [8].
- Total protein (TP) levels, with an OR of 1.95 (95% CI: 1.14, 3.53) 8.
- Immediate PORT use, with an OR of 3.13 (95% CI: 1.18, 8.30) 8.
- The area under the curve (AUC) of the receiver-operating characteristic curve for TP was 0.63, and the cutoff value was 5.9 g/dL 8.
Comparison of CLABSI Rates
Comparison of CLABSI rates between different types of central lines has been studied:
- TECs and PICCs were associated with higher CLABSI rates than ports, inpatient and ambulatory 9.
- PICCs were associated with a lower risk of CLABSI than were CVCs (relative risk [RR], 0.62; 95% confidence interval [CI], 0.40-0.94) 10.
- However, hospitalized patients may be just as likely to experience CLABSI with PICCs as with CVCs 10.