# Therapeutic vancomycin monitoring: a comparative analysis of high-performance liquid chromatography and chemiluminescent microparticle immunoassay methods in liver transplant recipients

## TL;DR

This study compares two methods for measuring vancomycin levels in liver transplant patients and finds that HPLC is more accurate and reliable than CMIA.

## Contribution

The study demonstrates that HPLC provides more accurate vancomycin monitoring in liver transplant recipients compared to CMIA.

## Key findings

- HPLC showed superior accuracy and precision in measuring vancomycin concentrations in liver transplant recipients.
- HPLC detected significant differences in trough and intermediate concentrations in patients with nephrotoxicity, which CMIA did not.
- Pharmacokinetic variables like half-life and AUC were significantly different with HPLC but not with CMIA.

## Abstract

Vancomycin is a glycopeptide antibiotic of choice for treating serious Gram-positive bacterial infections, including methicillin-resistant Staphylococcus aureus (MRSA). However, its therapeutic efficacy and risk of nephrotoxicity are closely related to maintaining specific serum concentration levels. Liver transplant recipients (LTRs) require precise therapeutic drug monitoring (TDM) due to altered pharmacokinetics. This study compares the accuracy and precision of two vancomycin measurement methods—chemiluminescent microparticle immunoassay (CMIA) and high-performance liquid chromatography (HPLC) in LTRs.

The cross-sectional study was conducted over 11 months at the Abu-Ali Sina Solid Organ Transplant Hospital in Shiraz, Iran. The study included 34 adult LTRs on vancomycin treatment, excluding those with hypersensitivity, chronic kidney disease, burn injuries, or receiving phenytoin. Blood samples were collected at different intervals post-vancomycin administration and analyzed using both CMIA and HPLC methods.

HPLC demonstrated superior accuracy and precision in measuring vancomycin concentrations, particularly in identifying patients with vancomycin-induced nephrotoxicity. Significantly higher trough (p-value: 0.026) and intermediate (p-value: 0.49) concentrations were detected by HPLC in patients experiencing nephrotoxicity, whereas CMIA did not show significant differences between groups. Pharmacokinetic variables such as half-life (p-value: 0.024) and AUC (p-value:0.037), measured by HPLC, were significantly different between LTRs with and without nephrotoxicity, which was not observed with CMIA.

HPLC is more sensitive and reliable than CMIA for measuring vancomycin levels in LTRs, which is critical for optimizing vancomycin therapy and preventing adverse effects. The research suggests that HPLC should be the preferred method for vancomycin TDM in LTRs and further multicenter studies are recommended to validate these results.