Pyelonephritis diagnostic study of choice

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sadaf Sharfaei M.D.[2]

Overview

Urinalysis and urine culture with susceptibility testing might confirm the diagnosis of pyelonephritis. Pyelonephritis must be suspected if the patient has urinary symptoms including dysuria, urgency, frequency, or suprapubic pain, along with fever, chills, flank pain, pelvic or perineal pain. Imaging would not be necessary for patients with pyelonephritis, unless in patients with severe and refractory illness or suspected urinary tract obstruction.

Diagnostic Study of Choice

Study of choice

Urinalysis and urine culture with susceptibility testing might confirm the diagnosis of pyelonephritis.^[1]^[2]^[3]
Pyelonephritis must be suspected if the patient has urinary symptoms including dysuria, urgency, frequency, or suprapubic pain, along with fever, chills, flank pain, pelvic or perineal pain.
Imaging would not be necessary for patients with pyelonephritis, unless in patients with severe and refractory illness or suspected urinary tract obstruction.

The comparison of various diagnostic studies for pyelonephritis

Test			Sensitivity	Specificity
Urinalysis	WBC	> 5 WBCs/HPF	72-95%	48-82%
	WBC	> 10 WBCs/HPF	58-82%	65-86%
	RBC	+	44%	88%
	Leukocyte esterase test (LET)	+	74-96%	94-98%
	Nitrite test (NPT)	+	35-85%	92-100%
	Combined leukocyte esterase-nitrite tests	Either test +	75-84%	82-98%
	Gram stain of uncentrifuged urine	> 1 bacterium per HPF	93%	95%
	Urinary neutrophil gelatinase-associated lipocalin (NGAL)	> 29.4 ng/mL	92.5%	90.7%
	Urinary neutrophil gelatinase-associated lipocalin (NGAL)	> 7.32 ng/ml	81.3%	66%
Urine culture		+	90%
Blood culture		+	20%

References

↑ Ramakrishnan K, Scheid DC (2005). “Diagnosis and management of acute pyelonephritis in adults”. Am Fam Physician. 71 (5): 933–42. PMID 15768623.
↑ Hoverman IV, Gentry LO, Jones DW, Guerriero WG (1980). “Intrarenal abscess. Report of 14 cases”. Arch Intern Med. 140 (7): 914–6. PMID 6992728.
↑ Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG; et al. (2011). “International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases”. Clin Infect Dis. 52 (5): e103–20. doi:10.1093/cid/ciq257. PMID 21292654.

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[pmid15768623-1] Ramakrishnan K, Scheid DC (2005). “Diagnosis and management of acute pyelonephritis in adults”. Am Fam Physician. 71 (5): 933–42. PMID 15768623.

[pmid6992728-2] Hoverman IV, Gentry LO, Jones DW, Guerriero WG (1980). “Intrarenal abscess. Report of 14 cases”. Arch Intern Med. 140 (7): 914–6. PMID 6992728.

[pmid21292654-3] Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG; et al. (2011). “International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases”. Clin Infect Dis. 52 (5): e103–20. doi:10.1093/cid/ciq257. PMID 21292654.

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