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Establishment of reference intervals for thyroid function tests during pregnancy
1114
Abstracts
Conclusions: These data suggest that the published healthy population sex-specific 99th may not be suitable for women in labor. doi:10.1016/j.clinbiochem.2012.07.049
P547 Investigation of the clinical utility of the measurement of clinical and biochemical markers at late mid-term of pregnancy to identify women who will develop preeclampsia within a few weeks J. Masséa, Y. Giguèreb, S. Thériaultb, M. Charlandb, E. Bujoldb, F. Rousseaub, J. Lafondc, J.C. Forestb a Centre Hospitalier Affilié Universitaire de Québec, Québec, QC, Canada b Centre de Recherche, Centre Hospitalier Universitaire de Québec et Faculté de Médecine, Université Laval, Québec, QC, Canada c Dept. Biological Sciences, UQAM, Montréal, QC, Canada Objective: To examine, in a prospective study, the performance of selected clinical (mean arterial pressure, body mass index) and biochemical markers (PlGF, sFlt-1, inhibinA, PAPP-A) for identifying during late mid-term pregnancy women who are at risk of developing preeclampsia PE within a few weeks. Design: A nested case–control study was performed from a cohort (7929 women) including 214 cases of hypertension disorders of pregnancy HDP of which 88 developed PE (1.2%) and 44 severe PE (0.6%). Each case was matched with two normal pregnancies for maternal age, gestational age at recruitment, ethnicity, parity, and smoking status. Biomarker results measured between 20 and 32 weeks gestation were expressed as multiples of medians which were determined for each gestational week. Multivariate logistic regression analyses were performed to develop prediction algorithms. Results: The regression models discriminated the affected from normal pregnancies as indicated by an area under the ROC curve of 0.8. But at a 5% false positive rate, only 28% of the women who have developed HDP would have been detected. Even when the statistical analyses were limited to severe PE, the performance was poor: sensitivity 30%, positive predictive value 2.7%. Conclusion: Neither individual candidate markers nor multivariate risk algorithm using an a priori combination of selected clinical and biochemical markers reached a performance justifying implementation as a screening procedure in a low-risk population. These results emphasize the necessity to take into consideration environment, population and health care settings influencing prevalence and characteristics of HDP before promoting wide implementation of such screening strategies. doi:10.1016/j.clinbiochem.2012.07.050
P548 Establishment of reference intervals for thyroid function tests during pregnancy K. Mourabit Amari, L. Bondaz, J. Girouard, C. Gagnon, J. Weisnagel, J.-C. Forest, Y. Giguère Centre Hospitalier Universitaire de Québec, Canada Objective: The study aims to determine reference intervals for TSH, free T4 and total T3 in pregnant women for use in our center (CHUQ). Design: Leftover serum samples from routine blood work during pregnancy performed in our laboratory were analyzed on the Roche Modular platform. Pregnancy age was obtained from laboratory information system.
Methods: Samples were analyzed on Roche E170 Modular automated analyzer for TSH, free T4, total T3, β-HCG, albumin and anti-TPO antibodies. Percentiles for TSH, free T4 and Total T3 were computed for every trimester. ANOVA on logarithmically transformed test results was performed to compare between trimesters for every thyroid parameter. Results: 546 samples were collected, including 60 (11.0%) antiTPO positive samples, which were excluded from reference population. TSH, free T4 and total T3 in reference population differed from current CHUQ adult reference range and significant variation between trimester was observed for TSH and free T4 (Table 1). Table 1 Summary of trimester-based ANOVA performed on log transformed thyroid function test results with corresponding trimester based test distribution and CHUQ reference ranges. Parameter
TSH
Free T4
Total T3
Transformation
Ln (TSH)·2
Ln (fT4)
Ln (tT3)
Comparison T1 vs T2 T1 vs T3 T2 vs T3
p b 0.001 p = 0.0033 p = 0.14
p b 0.001 p b 0.001 p b 0.001
p = 0.0542 p = 0.2339 p = 0.5039
Centile
2.5 50 97.5 Adult Centile
TSH (mlU/L)
Free T4 (pmol/L)
T1 (n = 194)
T2 (n = 142)
T3 (n = 150)
T1 (n = 194)
T2 (n = 142)
T3 (n = 150)
0.45 1.34 4.35 0.25·5
0.51 1.58 4.54
0.47 1.88 4.78
10.36 13.55 17.81 12·22
9.54 12.42 16.32
8.64
T3T (nmol/L) T1 (n = 194)
2.5 50 97.5 Adult
11.18 15.14
T2 (n = 142)
T3 (n = 150)
1.81
1.80
1.80
2.51 3.60 1.2·3.0
2.59 3.73
2.56 3.92
Conclusions: It is relevant to perform in‐house validation of reference intervals for use of thyroid function tests in pregnancy since distribution for TSH, freeT4 and Total T3 differs during pregnancy; thyroid hormones are important for fetal development and guidelines [1] recommend pregnancy specific reference intervals. (1) Thyroid 2011; 21:1081–125. doi:10.1016/j.clinbiochem.2012.07.051
P550 Suivi post-implantation d'un test de fibronectine fœtale pour la prévention du risque d'accouchement pré-terme Carine Nyalendo, Soumaya Zénagui, Fabienne Parente, Marie-Josée Bédard, Lyne Labrecque Centre Hospitalier de l'Université de Montréal, 1058, rue Saint-Denis, Montréal, Québec, H2X 3J4 Objectifs: La mesure de la fibronectine fœtale (FNF) permet d'évaluer le risque d'accouchement pré-terme, avec une excellente valeur prédictive négative (VPN). Nous avons évalué les gains obtenus suite à l'implantation du test de FNF dans un centre tertiaire, de façon théorique et dans une étude de suivi post-implantation. Méthodes: Nous avons mesuré la FNF dans 21 échantillons obtenus à l'aveugle des cliniciens. Une étude coûts/bénéfices a été complétée en considérant un temps d'observation maximal de 4 heures suite à un résultat négatif. Nous avons ensuite fait un suivi de son utilisation réelle dans les 12 mois suivants son implantation.
Abstracts
Conclusions: These data suggest that the published healthy population sex-specific 99th may not be suitable for women in labor. doi:10.1016/j.clinbiochem.2012.07.049
P547 Investigation of the clinical utility of the measurement of clinical and biochemical markers at late mid-term of pregnancy to identify women who will develop preeclampsia within a few weeks J. Masséa, Y. Giguèreb, S. Thériaultb, M. Charlandb, E. Bujoldb, F. Rousseaub, J. Lafondc, J.C. Forestb a Centre Hospitalier Affilié Universitaire de Québec, Québec, QC, Canada b Centre de Recherche, Centre Hospitalier Universitaire de Québec et Faculté de Médecine, Université Laval, Québec, QC, Canada c Dept. Biological Sciences, UQAM, Montréal, QC, Canada Objective: To examine, in a prospective study, the performance of selected clinical (mean arterial pressure, body mass index) and biochemical markers (PlGF, sFlt-1, inhibinA, PAPP-A) for identifying during late mid-term pregnancy women who are at risk of developing preeclampsia PE within a few weeks. Design: A nested case–control study was performed from a cohort (7929 women) including 214 cases of hypertension disorders of pregnancy HDP of which 88 developed PE (1.2%) and 44 severe PE (0.6%). Each case was matched with two normal pregnancies for maternal age, gestational age at recruitment, ethnicity, parity, and smoking status. Biomarker results measured between 20 and 32 weeks gestation were expressed as multiples of medians which were determined for each gestational week. Multivariate logistic regression analyses were performed to develop prediction algorithms. Results: The regression models discriminated the affected from normal pregnancies as indicated by an area under the ROC curve of 0.8. But at a 5% false positive rate, only 28% of the women who have developed HDP would have been detected. Even when the statistical analyses were limited to severe PE, the performance was poor: sensitivity 30%, positive predictive value 2.7%. Conclusion: Neither individual candidate markers nor multivariate risk algorithm using an a priori combination of selected clinical and biochemical markers reached a performance justifying implementation as a screening procedure in a low-risk population. These results emphasize the necessity to take into consideration environment, population and health care settings influencing prevalence and characteristics of HDP before promoting wide implementation of such screening strategies. doi:10.1016/j.clinbiochem.2012.07.050
P548 Establishment of reference intervals for thyroid function tests during pregnancy K. Mourabit Amari, L. Bondaz, J. Girouard, C. Gagnon, J. Weisnagel, J.-C. Forest, Y. Giguère Centre Hospitalier Universitaire de Québec, Canada Objective: The study aims to determine reference intervals for TSH, free T4 and total T3 in pregnant women for use in our center (CHUQ). Design: Leftover serum samples from routine blood work during pregnancy performed in our laboratory were analyzed on the Roche Modular platform. Pregnancy age was obtained from laboratory information system.
Methods: Samples were analyzed on Roche E170 Modular automated analyzer for TSH, free T4, total T3, β-HCG, albumin and anti-TPO antibodies. Percentiles for TSH, free T4 and Total T3 were computed for every trimester. ANOVA on logarithmically transformed test results was performed to compare between trimesters for every thyroid parameter. Results: 546 samples were collected, including 60 (11.0%) antiTPO positive samples, which were excluded from reference population. TSH, free T4 and total T3 in reference population differed from current CHUQ adult reference range and significant variation between trimester was observed for TSH and free T4 (Table 1). Table 1 Summary of trimester-based ANOVA performed on log transformed thyroid function test results with corresponding trimester based test distribution and CHUQ reference ranges. Parameter
TSH
Free T4
Total T3
Transformation
Ln (TSH)·2
Ln (fT4)
Ln (tT3)
Comparison T1 vs T2 T1 vs T3 T2 vs T3
p b 0.001 p = 0.0033 p = 0.14
p b 0.001 p b 0.001 p b 0.001
p = 0.0542 p = 0.2339 p = 0.5039
Centile
2.5 50 97.5 Adult Centile
TSH (mlU/L)
Free T4 (pmol/L)
T1 (n = 194)
T2 (n = 142)
T3 (n = 150)
T1 (n = 194)
T2 (n = 142)
T3 (n = 150)
0.45 1.34 4.35 0.25·5
0.51 1.58 4.54
0.47 1.88 4.78
10.36 13.55 17.81 12·22
9.54 12.42 16.32
8.64
T3T (nmol/L) T1 (n = 194)
2.5 50 97.5 Adult
11.18 15.14
T2 (n = 142)
T3 (n = 150)
1.81
1.80
1.80
2.51 3.60 1.2·3.0
2.59 3.73
2.56 3.92
Conclusions: It is relevant to perform in‐house validation of reference intervals for use of thyroid function tests in pregnancy since distribution for TSH, freeT4 and Total T3 differs during pregnancy; thyroid hormones are important for fetal development and guidelines [1] recommend pregnancy specific reference intervals. (1) Thyroid 2011; 21:1081–125. doi:10.1016/j.clinbiochem.2012.07.051
P550 Suivi post-implantation d'un test de fibronectine fœtale pour la prévention du risque d'accouchement pré-terme Carine Nyalendo, Soumaya Zénagui, Fabienne Parente, Marie-Josée Bédard, Lyne Labrecque Centre Hospitalier de l'Université de Montréal, 1058, rue Saint-Denis, Montréal, Québec, H2X 3J4 Objectifs: La mesure de la fibronectine fœtale (FNF) permet d'évaluer le risque d'accouchement pré-terme, avec une excellente valeur prédictive négative (VPN). Nous avons évalué les gains obtenus suite à l'implantation du test de FNF dans un centre tertiaire, de façon théorique et dans une étude de suivi post-implantation. Méthodes: Nous avons mesuré la FNF dans 21 échantillons obtenus à l'aveugle des cliniciens. Une étude coûts/bénéfices a été complétée en considérant un temps d'observation maximal de 4 heures suite à un résultat négatif. Nous avons ensuite fait un suivi de son utilisation réelle dans les 12 mois suivants son implantation.