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Kidney Week

Abstract: SA-PO1106

Sterile Pyuria Is Common in CKD and Differential Counting of Urinary Leukocytes Could Be Helpful for Predicting Urinary Tract Infection

Session Information

Category: Pathology and Lab Medicine

  • 1502 Pathology and Lab Medicine: Clinical

Authors

  • Choi, Hye Min, Myongji Hospital, Goyang-si, Korea (the Republic of)
  • Kwon, Young Eun, Myoungji hospital, Goyang-si, Gyeonggi-do, seoul, Korea (the Republic of)
  • Oh, Dong-jin, Myongji Hospital, Koyang, Korea (the Republic of)
Background

Pyuria is a helpful marker for urinary tract infection (UTI) in general population. Meanwhile, pyuria is not infrequent in advanced chronic kidney disease (CKD) patients. There has been assumption that sterile pyuria can be seen in CKD due to chronic renal parenchymal inflammation. However, there are limited data on whether CKD increases the rate of pyuria or how we should interpret pyuria of CKD. Here, we aimed to investigate the prevalence and characteristics of pyruia of CKD.

Methods

This was a cross-sectional study of a single center.
Urine analysis (UA) was performed in all the stable hemodialysis (HD) and non-dialysis CKD (eGFR < 60ml/min/1.73m2) patients of the outpatient clinic during 3 month. Patients with urinary symptom or recent history of antibiotics were excluded.
Pyuria was defined as white blood cell (WBC) ≥ 5/high power filed by microscopy. WBC differential counting was done in case UA showed pyuria. Culture-positive pyuria was defined as UTI.

Results

UA was examined in 70 HD patients who voids at least once every day and 228 non-dialysis CKD patients.
The prevalence of pyuria was 51.4% (male (M) 36.1%, female (F) 67.6%) in HD and 22.4% (M 12.5%, F 39.3%) in CKD population, and were much higher compared to that of the age-matched general population (overall 7.3%, M 1.6%, F 19.1%) which was obtained from health examination in the same hospital (n=4897).
Of the 86 patients with pyuria, only 22.1% were proven to be UTI (11.1% of HD and 30.0% of CKD). Female gender, lower stages of CKD, more leukocytes in urine, and positive nitrite-response were associated with true UTI in pyuric patients.
As for differential counting, the majority of urinary leukocytes were still neutrophils even in sterile pyuria. However, the percentage of neutrophil was significantly lower (69.1% vs 92.5%), and the percentages of lymphocyte and monocyte were higher (18.5% vs 4.9% and 9.9% vs 2.1%, respectively) in sterile pyuria compared with UTI. In multivariate logistic regression analysis, the degree of pyuria, nitrite response, and the percentage of neutrophil remained independently associated with UTI in pyuric patients.

Conclusion

Pyuria is more common in CKD than in the general population. Differential cell counting of urinary leukocytes could be helpful for predicting UTI in asymptomatic CKD patients with pyuria.