Final answer:
A positive test for leukocyte esterase and nitrites in a urinalysis typically suggests a urinary tract infection, which should be confirmed with a urine culture for accurate diagnosis and treatment planning.
Step-by-step explanation:
The presence of leukocyte esterase (LE) and nitrites in a urine sample are common indicators used in the diagnosis of urinary tract infections (UTIs). LE is an enzyme produced by leukocytes (white blood cells), and its presence in urine usually points to an active infection. Nitrites in urine indicate that certain types of bacteria, such as Escherichia coli or Klebsiella pneumoniae, may be present, as these organisms can convert nitrates to nitrites. Both LE and nitrites are tested quickly using a urine dipstick, but due to low specificity and sensitivity of these rapid tests, a positive result should be followed up with a urine culture to confirm the infection. Urine culture is performed on media such as blood agar and MacConkey agar to grow the bacteria for accurate identification and susceptibility testing, helpful for prescribing the proper antibiotic treatment. This test ideally requires a 'clean catch' of urine to avoid contamination with the normal microbiota of the external genitalia.