Utilizing Estimated Creatinine Excretion to Improve the Performance of Spot Urine Samples for the Determination of Proteinuria in Kidney Transplant Recipients

Abstract Kidney transplant recipients have higher incidence of human papillomavirus (HPV)-related malignancies, but studies on the natural history of HPV infection are insufficient, especially regarding in male recipients. The aim of this study was to evaluate the course of high-risk HPV (HR-HPV) infection after kidney allograft transplantation in male recipients: to estimate frequency and activity of HR-HPV infection under immune system suppression. Twenty male renal recipients (age 20 - 68) were enrolled in this investigation and examined in dynamics. Peripheral EDTA-blood samples and urine samples were collected from each patient 2 weeks, 6 months and 12 months after transplantation. Polymerase chain reaction (PCR) with consensus primers was used for initial detection of high range HPV types, a commercial qPCR kit for detection of HR-HPV load in urine samples and ELISA for detection of serum IgG class antibodies to HR-HPV L1-capsid protein. Overall, combining molecular (HR-HPV genomic sequences detected by real-time PCR) and serological studies (IgG class antibodies to HR-HPV L1-capsids’ protein), high frequency of HRHPV infection among male kidney transplant recipients (9/20; 45%) was showed. However, the majority of HR-HPV positive recipients (7/9; 78%) showed signs of infection clearance. It means that, despite the applied immune suppressive therapy, the host’s immune system is capable of dealing with HR-HPV infection up to the 12th month after transplantation. However, the sample size should be increased to enable through statistical analysis before final conclusions are made.

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First and second morning spot urine protein measurements for the assessment of proteinuria: a diagnostic accuracy study in kidney transplant recipients

BMC Nephrology ◽

10.1186/s12882-021-02406-x ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Maja Mrevlje ◽

Manca Oblak ◽

Gregor Mlinšek ◽

Jelka Lindič ◽

Jadranka-Buturović-Ponikvar ◽

...

Keyword(s):

Kidney Transplant ◽

Cross Sectional Study ◽

Low Grade ◽

Transplant Recipients ◽

Kidney Transplant Recipients ◽

Urine Protein ◽

Cross Sectional ◽

Spot Urine ◽

Protein Excretion ◽

Measures Of Agreement

Abstract Background Quantification of proteinuria in kidney transplant recipients is important for diagnostic and prognostic purposes. Apart from correlation tests, there have been few evaluations of spot urine protein measurements in kidney transplantation. Methods In this cross-sectional study involving 151 transplanted patients, we investigated measures of agreement (bias and accuracy) between the estimated protein excretion rate (ePER), determined from the protein-to-creatinine ratio in the first and second morning urine, and 24-h proteinuria and studied their performance at different levels of proteinuria. Measures of agreement were reanalyzed in relation to allograft histology in 76 patients with kidney biopsies performed for cause before enrolment in the study. Results For ePER in the first morning urine, percent bias ranged from 1 to 28% and accuracy (within 30% of 24-h collection) ranged from 56 to 73%. For the second morning urine, percent bias ranged from 2 to 11%, and accuracy ranged from 71 to 78%. The accuracy of ePER (within 30%) in first and second morning urine progressively increased from 56 and 71% for low-grade proteinuria (150–299 mg/day) to 60 and 74% for moderate proteinuria (300–999 mg/day), and to 73 and 78% for high-grade proteinuria (≥1000 mg/day). Measures of agreement were similar across histologic phenotypes of allograft injury. Conclusions The ability of ePER to accurately predict 24-h proteinuria in kidney transplant recipients is modest. However, accuracy improves with an increase in proteinuria. Given the similar accuracy of ePER measurements in first and second morning urine, second morning urine can be used to monitor protein excretion.

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