POS-289 PARAFFIN WASHOUT IMMUNOFLUORESCENCE TECHNIQUE IMPROVE SAFETY AND ADEQUACY OF NATIVE KIDNEY BIOPSY AND TRANSPLANT KIDNEY BIOPSY IN A TERTIARY TEACHING HOSPITAL

ABSTRACT

Introduction: Kidney biopsy (KB) tissues are usually dissected 0.5-1.0 cm for fresh sample immunofluorescence study (FSIF). Paraffin washed-out immunofluorescence (PWIF) technique doesn’t require segmentation of the kidney biopsy sample that may jeopardise the sample adequacy for histopathological examination (HPE). Hypothetically, it reduces biopsy passes and complications. We examine the safety and adequacy of native kidney biopsy (NKB) and transplant kidney biopsy (TKB) using the FSIF technique and PWIF technique in HPE preparation for immunofluorescent study. Methods: We retrospectively collected clinical history, blood results, and renal biopsy reports for all the patients who had undergone KB using electronic medical records at University Malaya Medical Centre, Kuala Lumpur, Malaysia from 1/1/2015 to 31/4/2021. We performed 1520 KBs (795 NKBs & 725 TKBs) and 1336 KBs with complete data analysed (670 NKBs & 666 TKBs). Sixty-one of the 670 (9.1%) NKBs and 48 of the 666 (7.2%) TKBs employed the PWIF method from 13/10/2020 to 31/4/2021 (6 months) because of the COVID-19 pandemic. We collected 62 NKBs and 65 TKBs from 13/10/2018 to 31/4/2019 (6 months) as the control group which used the FSIF method. The control is chosen as such to correlate with the same months of another year. Results: There were no statistically significant differences in the baseline characteristics between the two groups of each cohort respectively except for the ethnicity distribution in the TKB cohort (p=0.037) and INR in NKB and TKB cohorts (p=0.000 & p=0.002 respectively). PWIF group in NKB and TKB recorded lesser pass (p=0.000 for both), longer HPE core (p=0.001 & p=0.024 respectively), better HPE adequacy (p=0.006 & p=0.012 respectively). There were no statistical differences in the diagnostic yield, immediate pain, gross haematuria, haematoma, and admissions or prolong hospitalisation due to biopsy complications in both groups for NKB and TKB cohorts (Table 1 & 2). [Formula presented] Conclusions: Paraffin washed-out immunofluorescence technique increased the native and transplant kidney biopsy adequacy with a lesser pass and better biopsy sample adequacy for histopathological examination but no difference in the incidence of complications. However, a greater number of cases are required to assess the statistically significant difference in the incidence of complications. No conflict of interest