What is the diagnosis for a female patient presenting with dysuria, positive nitrates, negative leukocytes, mild hematuria (BLD 10), mild hemoglobinuria (UBG 8), and mild bilirubinemia (BIL 4), with no proteinuria?

Diagnosis: Urinary Tract Infection (UTI)

This patient has a urinary tract infection that warrants empiric antibiotic treatment despite the negative leukocyte esterase, because the positive nitrites combined with classic dysuria symptoms are sufficient for diagnosis. 1

Diagnostic Reasoning

Why This is a UTI Despite Negative Leukocytes

• Positive nitrites have 98% specificity for UTI, making them highly reliable when present, even though sensitivity is only 49% 2
• In women with typical lower urinary tract symptoms (dysuria, frequency, urgency), clinical diagnosis alone has >90% accuracy for UTI, and dipstick testing adds minimal diagnostic value 1
• The European Association of Urology explicitly advises against withholding antibiotics based solely on negative dipstick results, as symptoms guide treatment in uncomplicated cystitis 1
• Approximately 30% of children with positive urine cultures have negative urinalysis (negative leukocyte esterase, negative nitrites, and WBC <5/hpf), with 59% of these cases caused by non-E. coli organisms 3

Addressing the Other Urinalysis Findings

• Blood (BLD 10): Mild hematuria can occur with UTI due to bladder mucosal inflammation and does not change management 4
• Urobilinogen (UBG 8) and Bilirubin (BIL 4): These mildly elevated values are likely incidental findings unrelated to the acute dysuria presentation 4
• Negative protein: Helps exclude glomerular disease, supporting a lower urinary tract infection diagnosis 4

Treatment Approach

First-Line Antibiotic Options

Initiate empiric therapy immediately with one of the following 1:

• Nitrofurantoin for 5 days (preferred due to low resistance rates) 1, 5
• Fosfomycin trometamol as a single dose 1, 5
• Trimethoprim-sulfamethoxazole for 3 days 1, 5
• Trimethoprim alone for 3 days 1

Special Consideration for Negative Leukocyte Esterase

• The negative leukocyte esterase with positive nitrites suggests a possible non-E. coli organism 3
• If symptoms fail to improve with first-line therapy, consider that trimethoprim-sulfamethoxazole may have better coverage for non-E. coli organisms (82.2% sensitivity vs 71.3% for E. coli) 3
• Avoid fluoroquinolones as first-line therapy due to increased adverse effects and promotion of resistance 1

Follow-Up Strategy

• Reassess symptoms at 48-72 hours after initiating antibiotics 1
• If symptoms persist or recur within 2 weeks, obtain urine culture and antimicrobial susceptibility testing, then retreat with a 7-day course of a different agent 1
• No routine post-treatment urine culture is needed if symptoms resolve 5

Critical Pitfalls to Avoid

• Do not delay treatment waiting for urine culture in this straightforward presentation of dysuria with positive nitrites 1
• Do not assume anticoagulation or antiplatelet therapy explains the hematuria—this is not a satisfactory explanation and the hematuria is likely related to the UTI 2
• Do not order urine cytology or bladder cancer markers for this acute presentation with clear infectious etiology 2
• If the patient is menstruating or recently menstruated, the blood and trace findings could be contamination, but this does not change the UTI diagnosis given the positive nitrites and dysuria 6