Patient Participation in Urine Specific Gravity Screening for Arginine Vasopressin Deficiency in an Inpatient Neurosurgical Clinic.

OBJECTIVE

Detecting hypotonic urine (specific gravity < 1005 g/L) is crucial for the early identification of arginine vasopressin deficiency (AVP-deficiency), a common complication after pituitary surgery. This study aimed to evaluate the agreement between urine specific gravity measurements taken by patients using urine test strips and those taken by nurses using a refractometer, to assess the reliability of patient-conducted measurements for diagnosing this condition.

DESIGN

A prospective cohort study was conducted in a neurosurgical ward.

PATIENTS

The study included 110 participants who collectively provided 609 specific gravity measurements.

MEASUREMENTS

Specific gravity measurements were taken using Combur-10 urine test strips by patients and using an ATAGO MASTER-SUR/Nα refractometer by nurses. Agreement was analysed using Weighted Kappa and intraclass correlation coefficient (ICC).

RESULTS

Moderate agreement was found between patient-conducted measurements and those from the refractometer (Kappa = 0.47, ICC = 0.69). Substantial to good agreement was observed between patient and nurse measurements using urine test strips (Kappa = 0.82, ICC = 0.89). A threshold of 1.015 g/L in test strip measurements ensured no cases of hypotonic urine were missed, reducing the need for nurse-led testing by 50%. Patient satisfaction was high (mean 7.8), while nurse satisfaction was lower (mean 6.4).

CONCLUSIONS

Although patients are less accurate than nurses in measuring specific gravity, they can reliably screen for hypotonic urine in AVP-deficiency diagnostics using urine test strips. A higher cut-off point improves diagnostic accuracy, enhances patient participation and reduces the screening workload for nurses.