Leucocytes in urine without bacteria on culture (sterile pyuria)

Urine tests, away from any antibiotic

• Repeat urine microscopy and culture (midstream; enclose clinical information and recent antibiotics)
• Urine dipstick (blood, protein)
• Urine protein:creatinine ratio (spot sample)if neededDipstick positive for protein or blood, or renal context: proteinuria, haematuria and leucocyturia without infection are markers of renal involvement ^[2].

Blood tests

• Serum creatinine with eGFR
• FBCif needednon-French guidelineSuspected drug-induced interstitial nephritis (recent drug, rising creatinine): eosinophilia is one marker, also seen in schistosomiasis ^[1].

Depending on the context

• Chlamydia trachomatis and Neisseria gonorrhoeae NAAT (PCR) (separate request from the urine culture)if neededSexually active patient, especially young: C. trachomatis is the organism most often found in this situation ^[1]. The NABM forbids performing and billing this PCR “within” a urine microscopy and culture: prescribe it separately ^[3].
• Mycobacteria in urine: the whole of the first morning voiding, 3 days in a rowif neededUnexplained persistent leucocyturia, especially if the patient comes from an endemic region, is immunosuppressed or has lost weight unintentionally ^[1]. Second-line test, on specific prescription in light of the first results ^[3].
• Search for schistosome eggs in urineif neededStay in a schistosomiasis-endemic area, haematuria ^[1]. The NABM provides for the test on the 1st morning void or 24-hour urine ^[3]; the British review advises terminal urine collected between 12 h and 15 h, the peak of egg excretion ^[1].
• Schistosomiasis serology (if freshwater contact in an endemic area, at least 3 months after the last contact)if needednon-French guidelineThe UK Health Security Agency (UKHSA) screens for schistosomiasis after freshwater contact in an endemic area by blood count, search for red cells and eggs in urine, stool examination and serology, waiting at least 3 months after the last contact in a patient without symptoms ^[4]. The British general practice review on which the page relies proposes, if suspected, searching for eggs in terminal urine collected between noon and 15 h, without serology ^[1].