Usefulness of iodine/creatinine ratio from spot-urine samples to evaluate the effectiveness of low-iodine diet preparation for radioiodine therapy.
Clin Endocrinol (Oxf)
; 73(1): 114-8, 2010 Jul.
Article
em En
| MEDLINE
| ID: mdl-20050860
ABSTRACT
OBJECTIVE:
The success of a low-iodine diet (LID) is best determined by measurement of 24-h urine iodine (U-I) excretion. The aim of this study was to determine reliable estimates for 24-h U-I based on spot-urine samples and to provide cut-offs to determine the effectiveness of LID preparation.DESIGN:
We prospectively measured iodine levels in 193 patients based on 24-h- and spot-urine samples before radioactive iodine therapy. The iodine was expressed as the 24-h U-I excretion (microg/day) and as two different indices from spot urine, simple iodine concentration (simple I) and the iodine/creatinine (I/Cr) ratio. Poor LID preparation was defined as I excretion of >150 microg/day according to the 24-h U-I measurement.RESULTS:
The measured 24-h U-I was significantly higher than the two indices from spot urine (P < 0.001). However, there were statistically significant correlations between the 24-h U-I values and the two spot-urine-based indices; the correlation coefficient was 0.539 for simple I and 0.773 for I/Cr ratio (P < 0.001). The cut-off of I/Cr ratio for poor LID preparation was >66.2 microg/g Cr (sensitivity 96.4%, specificity 83.6%, positive predictive value 50.0% and negative predictive value 99.3%).CONCLUSIONS:
We demonstrated that the I/Cr ratio from spot urine could serve as a useful and reliable alternative to 24-h urine collection as it has acceptable diagnostic values for detecting poor LID preparation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Creatinina
/
Iodo
/
Radioisótopos do Iodo
Limite:
Adult
/
Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Clin Endocrinol (Oxf)
Ano de publicação:
2010
Tipo de documento:
Article