CEDIE   05498
CENTRO DE INVESTIGACIONES ENDOCRINOLOGICAS "DR. CESAR BERGADA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Growth Hormone (GH) AssayStandardization: Clinical Implication onSerum GH Cut-off Value for PharmacologicalTests Used to Diagnose GH Deficiency (GHD)in Children
Autor/es:
BALLERINI, MARÍA GABRIELA; CHALER, EDUARDO A.; FRUSTI, MAURO; LAZZATI, JUAN MANUEL; MACEIRAS, MERCEDES; BERGADÁ, IGNACIO; RIVAROLA, MARCO A.; BELGOROSKY, ALICIA; ROPELATO, MARÍA GABRIELA
Lugar:
Montevideo
Reunión:
Congreso; XXIII Annual Meeting of the Paediatrics Endocrinology Latinoamerican Society; 2012
Institución organizadora:
XXIII Annual Meeting of the Paediatrics Endocrinology Latinoamerican Society
Resumen:
GH deficiency (GHD) needs to be biochemically
confirmed by measurements of GH concentrations during pharmacological
stimulation tests (PhT). Recently, it has been introduce a new
recombinant highly purified standard (IS) for GH calibration assays
by manufactures and as a consequence, cut-off of PhT should be
revised. Aims: To evaluate the cut-off PhT value for recently modified
ICMA-GH calibrated with IS-98/574 and to determine the diagnostic
efficiency (DE) of the recalculated PhT cut-off. Material and
Methods: Serum GH concentration from 157 samples (baseline
and in response to arginine-clonidine stimulation tests) from 92 short
children were measured concomitantly by ICMA IS-80/505 (withdrawn
by Siemens) and current ICMA IS-98/574 assay from Siemens.
Passing-Bablok and ratio plot analyses were used for between-assay
comparisons. We calculated a new PhT cut-off in terms of IS 98/574
for fixed x value of 6.1 ng/mL (ICMA IS-80/505) using the regression
curve obtained. DE of the new ICMA IS-98/574 GH cut-off
to define GHD in children, was studied using other independent 43
peak GH serum samples (13/43 from GHD children, peak ICMA GH
IS-80/505<6.1 ng/mL) by ROC curve analysis. Results: ICMA-GH
IS-98/574 results were negatively biased compared to ICMA-GH
IS-80/505 (GH IS-98/574=0.74xGH IS-80/505+0.26, r2=0.979);
mean ratio (IS-98/574/IS-80/505): 0.79±0.17. The calculated cut-off
value for considering GH sufficient response to PhT was >4.7 ng/
mL in terms of GH IS-98/574 assay. Using this cut-off of 4.7 ng/mL,
all 13 GHD children were correctly diagnosed in terms of the recalibrated
GH IS-98/574 assay [DE: 100%; Sensitivity: 100% (95 IC%:
88.4100); Specificity: 100% (75.3100%)]. Conclusions: We
found a shift to lower GH results (in average: 20%) after the standardization
of the widely used ICMA-GH assay. Regarding our results,
the proposed cut-off value in terms of IS-98/574 (4.7 ng/mL) constitutes
a useful diagnostic tool for GHD in pediatric patients.Aims: To evaluate the cut-off PhT value for recently modified
ICMA-GH calibrated with IS-98/574 and to determine the diagnostic
efficiency (DE) of the recalculated PhT cut-off. Material and
Methods: Serum GH concentration from 157 samples (baseline
and in response to arginine-clonidine stimulation tests) from 92 short
children were measured concomitantly by ICMA IS-80/505 (withdrawn
by Siemens) and current ICMA IS-98/574 assay from Siemens.
Passing-Bablok and ratio plot analyses were used for between-assay
comparisons. We calculated a new PhT cut-off in terms of IS 98/574
for fixed x value of 6.1 ng/mL (ICMA IS-80/505) using the regression
curve obtained. DE of the new ICMA IS-98/574 GH cut-off
to define GHD in children, was studied using other independent 43
peak GH serum samples (13/43 from GHD children, peak ICMA GH
IS-80/505<6.1 ng/mL) by ROC curve analysis. Results: ICMA-GH
IS-98/574 results were negatively biased compared to ICMA-GH
IS-80/505 (GH IS-98/574=0.74xGH IS-80/505+0.26, r2=0.979);
mean ratio (IS-98/574/IS-80/505): 0.79±0.17. The calculated cut-off
value for considering GH sufficient response to PhT was >4.7 ng/
mL in terms of GH IS-98/574 assay. Using this cut-off of 4.7 ng/mL,
all 13 GHD children were correctly diagnosed in terms of the recalibrated
GH IS-98/574 assay [DE: 100%; Sensitivity: 100% (95 IC%:
88.4100); Specificity: 100% (75.3100%)]. Conclusions: We
found a shift to lower GH results (in average: 20%) after the standardization
of the widely used ICMA-GH assay. Regarding our results,
the proposed cut-off value in terms of IS-98/574 (4.7 ng/mL) constitutes
a useful diagnostic tool for GHD in pediatric patients.Material and
Methods: Serum GH concentration from 157 samples (baseline
and in response to arginine-clonidine stimulation tests) from 92 short
children were measured concomitantly by ICMA IS-80/505 (withdrawn
by Siemens) and current ICMA IS-98/574 assay from Siemens.
Passing-Bablok and ratio plot analyses were used for between-assay
comparisons. We calculated a new PhT cut-off in terms of IS 98/574
for fixed x value of 6.1 ng/mL (ICMA IS-80/505) using the regression
curve obtained. DE of the new ICMA IS-98/574 GH cut-off
to define GHD in children, was studied using other independent 43
peak GH serum samples (13/43 from GHD children, peak ICMA GH
IS-80/505<6.1 ng/mL) by ROC curve analysis. Results: ICMA-GH
IS-98/574 results were negatively biased compared to ICMA-GH
IS-80/505 (GH IS-98/574=0.74xGH IS-80/505+0.26, r2=0.979);
mean ratio (IS-98/574/IS-80/505): 0.79±0.17. The calculated cut-off
value for considering GH sufficient response to PhT was >4.7 ng/
mL in terms of GH IS-98/574 assay. Using this cut-off of 4.7 ng/mL,
all 13 GHD children were correctly diagnosed in terms of the recalibrated
GH IS-98/574 assay [DE: 100%; Sensitivity: 100% (95 IC%:
88.4100); Specificity: 100% (75.3100%)]. Conclusions: We
found a shift to lower GH results (in average: 20%) after the standardization
of the widely used ICMA-GH assay. Regarding our results,
the proposed cut-off value in terms of IS-98/574 (4.7 ng/mL) constitutes
a useful diagnostic tool for GHD in pediatric patients.Serum GH concentration from 157 samples (baseline
and in response to arginine-clonidine stimulation tests) from 92 short
children were measured concomitantly by ICMA IS-80/505 (withdrawn
by Siemens) and current ICMA IS-98/574 assay from Siemens.
Passing-Bablok and ratio plot analyses were used for between-assay
comparisons. We calculated a new PhT cut-off in terms of IS 98/574
for fixed x value of 6.1 ng/mL (ICMA IS-80/505) using the regression
curve obtained. DE of the new ICMA IS-98/574 GH cut-off
to define GHD in children, was studied using other independent 43
peak GH serum samples (13/43 from GHD children, peak ICMA GH
IS-80/505<6.1 ng/mL) by ROC curve analysis. Results: ICMA-GH
IS-98/574 results were negatively biased compared to ICMA-GH
IS-80/505 (GH IS-98/574=0.74xGH IS-80/505+0.26, r2=0.979);
mean ratio (IS-98/574/IS-80/505): 0.79±0.17. The calculated cut-off
value for considering GH sufficient response to PhT was >4.7 ng/
mL in terms of GH IS-98/574 assay. Using this cut-off of 4.7 ng/mL,
all 13 GHD children were correctly diagnosed in terms of the recalibrated
GH IS-98/574 assay [DE: 100%; Sensitivity: 100% (95 IC%:
88.4100); Specificity: 100% (75.3100%)]. Conclusions: We
found a shift to lower GH results (in average: 20%) after the standardization
of the widely used ICMA-GH assay. Regarding our results,
the proposed cut-off value in terms of IS-98/574 (4.7 ng/mL) constitutes
a useful diagnostic tool for GHD in pediatric patients.Results: ICMA-GH
IS-98/574 results were negatively biased compared to ICMA-GH
IS-80/505 (GH IS-98/574=0.74xGH IS-80/505+0.26, r2=0.979);
mean ratio (IS-98/574/IS-80/505): 0.79±0.17. The calculated cut-off
value for considering GH sufficient response to PhT was >4.7 ng/
mL in terms of GH IS-98/574 assay. Using this cut-off of 4.7 ng/mL,
all 13 GHD children were correctly diagnosed in terms of the recalibrated
GH IS-98/574 assay [DE: 100%; Sensitivity: 100% (95 IC%:
88.4100); Specificity: 100% (75.3100%)]. Conclusions: We
found a shift to lower GH results (in average: 20%) after the standardization
of the widely used ICMA-GH assay. Regarding our results,
the proposed cut-off value in terms of IS-98/574 (4.7 ng/mL) constitutes
a useful diagnostic tool for GHD in pediatric patients.2=0.979);
mean ratio (IS-98/574/IS-80/505): 0.79±0.17. The calculated cut-off
value for considering GH sufficient response to PhT was >4.7 ng/
mL in terms of GH IS-98/574 assay. Using this cut-off of 4.7 ng/mL,
all 13 GHD children were correctly diagnosed in terms of the recalibrated
GH IS-98/574 assay [DE: 100%; Sensitivity: 100% (95 IC%:
88.4100); Specificity: 100% (75.3100%)]. Conclusions: We
found a shift to lower GH results (in average: 20%) after the standardization
of the widely used ICMA-GH assay. Regarding our results,
the proposed cut-off value in terms of IS-98/574 (4.7 ng/mL) constitutes
a useful diagnostic tool for GHD in pediatric patients.Conclusions: We
found a shift to lower GH results (in average: 20%) after the standardization
of the widely used ICMA-GH assay. Regarding our results,
the proposed cut-off value in terms of IS-98/574 (4.7 ng/mL) constitutes
a useful diagnostic tool for GHD in pediatric patients.