TY - JOUR

T1 - Measurement of urinary 5-HIAA

T2 - correlation between spot versus 24-h urine collection

AU - Calanchini, Matilde

AU - Tadman, Michael

AU - Krogh, Jesper

AU - Fabbri, Andrea

AU - Grossman, Ashley

AU - Shine, Brian

PY - 2019/8/1

Y1 - 2019/8/1

N2 - Background: The 24-h urinary output of 5-hydroxyindoleacetic acid (5-HIAA) is used to monitor disease progression and treatment responses of neuroendocrine neoplasms (NENs). Several conditions are required for 5-HIAA assay, involving urine collection/preservation and food/drug restrictions.Aim: To evaluate the correlation between 5-HIAA concentration in a spot urine sample and the output in a 24-h urine collection, and whether spot urine specimens can replace 24-h collection.Methods: Patients with NENs or symptoms suggestive of NENs were asked to provide a separate spot urine at the end of the 24-h urine collection for 5-HIAA assessment. The upper reference limit for 24-h urinary 5-HIAA was 40 µmol/24 h. 5-HIAA measurements in spot urine samples were corrected for variation in urine flow rate by expressing results as a ratio to creatinine concentration.Results: We included 136 paired urinary samples for 5-HIAA assessment from 111 patients (100 NENs). The correlation between 5-HIAA values measured in 24-h and spot urines was r = +0.863 (P < 0.001) and r = +0.840 (P < 0.001) including only NEN patients. Using the 24-h urinary 5-HIAA as reference method, the AUC on ROC analysis for spot urinary 5-HIAA was 0.948 (95% CI, 0.914-0.983; P < 0.001), attaining a sensitivity of 83% and specificity of 95% using 5.3 mol/mmol as cut-off for the spot urine. The AUC among NEN patients alone was 0.945 (95% CI, 0.904-0.987; P < 0.001).Conclusions: The ratio of 5-HIAA to creatinine in a spot urine could replace the measurement of 5-HIAA output in a 24-h urine collection, especially for follow-up of patients with known elevated 5-HIAA levels.

AB - Background: The 24-h urinary output of 5-hydroxyindoleacetic acid (5-HIAA) is used to monitor disease progression and treatment responses of neuroendocrine neoplasms (NENs). Several conditions are required for 5-HIAA assay, involving urine collection/preservation and food/drug restrictions.Aim: To evaluate the correlation between 5-HIAA concentration in a spot urine sample and the output in a 24-h urine collection, and whether spot urine specimens can replace 24-h collection.Methods: Patients with NENs or symptoms suggestive of NENs were asked to provide a separate spot urine at the end of the 24-h urine collection for 5-HIAA assessment. The upper reference limit for 24-h urinary 5-HIAA was 40 µmol/24 h. 5-HIAA measurements in spot urine samples were corrected for variation in urine flow rate by expressing results as a ratio to creatinine concentration.Results: We included 136 paired urinary samples for 5-HIAA assessment from 111 patients (100 NENs). The correlation between 5-HIAA values measured in 24-h and spot urines was r = +0.863 (P < 0.001) and r = +0.840 (P < 0.001) including only NEN patients. Using the 24-h urinary 5-HIAA as reference method, the AUC on ROC analysis for spot urinary 5-HIAA was 0.948 (95% CI, 0.914-0.983; P < 0.001), attaining a sensitivity of 83% and specificity of 95% using 5.3 mol/mmol as cut-off for the spot urine. The AUC among NEN patients alone was 0.945 (95% CI, 0.904-0.987; P < 0.001).Conclusions: The ratio of 5-HIAA to creatinine in a spot urine could replace the measurement of 5-HIAA output in a 24-h urine collection, especially for follow-up of patients with known elevated 5-HIAA levels.

U2 - 10.1530/EC-19-0269

DO - 10.1530/EC-19-0269

M3 - Journal article

VL - 8

SP - 1082

EP - 1088

JO - Endocrine Connections

JF - Endocrine Connections

SN - 2049-3614

IS - 8

ER -