Published: 2018-01-24

Utility of urinary gram stain as a diagnostic method for urinary tract infection

Vyankatesh T. Anchinmane, Kamal Preet, Shilpa Sankhe


Background: Urinary tract infection (UTI) is one of the most common infections in humans. Timely diagnosis and treatment are necessary to reduce the complications from UTI. Urine culture is still the gold standard diagnostic test for UTI, however it is costly and time consuming. The present study was conducted to compare the utility of urinary gram stain, microscopy of centrifuged urine sample and urine culture for the diagnosis of UTI.

Methods: 100 urine samples were processed for gram stain, culture and microscopy. Urinary gram stain findings were correlated with microscopy and culture results. Using urine culture as gold standard, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of urinary gram stain were assessed for the diagnosis of UTI.

Results: The accuracy of urinary gram stain for detection of UTI was 97%.

Conclusions: Urinary gram stain is a reliable diagnostic test for early detection of UTI.


Gram stain, Urinary tract infection

Full Text:



Moshaver B, Boer DF, Kreileman HE, Kramer E, Stegeman C, Groeneveld, P. Fast and accurate prediction of positive and negative urine cultures by flow cytometry. BMC Infectious Diseases. 2016;17(6):1557-64.

Robinson JL, Finlay JC, Lang ME, Bortolussi R. Urinary tract infections in infants and children: diagnosis and management. Paediatr Child Health. 2014;19(6):315-9.

Lockhart GR, Lewander WJ, Cimini DM, Josephson SL, Linakis JG. Use of urinary gram stain for detection of urinary tract infection in infants. Ann Emerg Med. 1995;25(1):31-5.

Benito FJ, García RA, Trebolazabala QN, Mintegi RS, Vázquez RM, Urra ZE. Gram stain and dipstick as diagnostic methods for urinary tract infection in febrile infants. An Esp Pediatr. 2000;53(6):561-6.

Arslan S, Caksen H, Rastgeldi L, Uner A, Oner AF, Odabaş D. Use of urinary gram stain for detection of urinary tract infection in childhood. Yale J Biol Med. 2002;75(2):73-8.

Patil SS, Mahale K, Krishna S, Mariraj J, Kalabhavi AS, Sathyanarayan MS. Evaluation of gram stain of uncentrifuged urine as a screening method for diagnosis of urinary tract infections. Curr Res Med Med Sci. 2011;1(2):19-21.

Ross JH, Kay R. Pediatric urinary tract infection and reflux. Am Fam Physician. 1999;59(6):1472-78.

Madersbacher S, Thalhammer F, Marberger M. Pathogenesis and management of recurrent urinary tract infection in women. Curr Opin Urol. 2000;10(1):29-33.

Ferris JA. Comparison and standardization of the urine microscopic examination. Lab Med. 1983;14:659-62.

Tambyah PA, Maki DG. Catheter associated urinary tract infection in rarely symptomatic: a prospective study of 1, 497 catheterized patients. Arch Intern Med. 2000;160(5):678-82.

Wennerstrom M, Hansson S, Jodal U, Sixt R, Stokland E. Renal function 16 to 26 years after the first urinary tract infection in childhood. Arch Pediatr Adolesc Med. 2000;154(4):339-45.

Gyory AZ, Hawkins T, Ross M, McLennan J, Ibels L. Clinical value of urine microscopy by manual and automated methods. Lab Hematol. 1998;4:211-6.