Outcome Validation of the Beckman Coulter Access Analyzer in a Second-Trimester Down Syndrome Serum Screening Application

MacRae, Andrew R.; Gardner, Humphrey; Allen, Lynn C.; Tokmakejian, Sonya; Lepage, Nathalie

doi:10.1373/49.1.69

Cited by 21 publications

(36 citation statements)

References 17 publications

(20 reference statements)

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“…When the median values of the serum markers at each gestational age were compared with the published values for Caucasian women (16), the median values of all the serum markers were higher in Korean women than Caucasian women. The range of ratios was highest for inhibin A (range, 1.5-1.9), followed by uE3, AFP, and hCG (Table 2).…”

Section: Resultsmentioning

confidence: 96%

“… * Comparison between unaffected pregnancies and Down syndrome pregnancies; P = 0.012, 0.001, 0.001, and < 0.001, by Student t test for AFP, hCG, uE3, and inhibin A respectively; † The log 10 means were estimated from the medians; ‡ Values in parentheses were reported by Wald et al (16). AFP, α-fetoprotein; hCG, human chorionic gonadotrophin; uE3, unconjugated Estriol.…”

Section: Figmentioning

confidence: 99%

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Korean-Specific Parameter Models for Calculating the Risk of Down Syndrome in the Second Trimester of Pregnancy

Kwon

Park

et al. 2011

J Korean Med Sci

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The purpose of the current study was to propose a Korean-specific parameter set for calculating the risk of Down syndrome in the second trimester of pregnancy and to determine the screening performances of triple and quadruple tests in Korean women. Using the data on triple or quadruple screening from three hospitals in Korea during 7 yr, we re-converted the concentrations of four serum markers to multiple of median values according to gestational age and maternal weight. After re-calculating the risk of Down syndrome in each pregnancy by multiplying maternal age-specific risk by the likelihood ratio values for the serum markers, screening performances and optimal cut-off values of triple and quadruple tests were analyzed. Among 16,077 pregnancies, 23 cases had Down syndrome (1.4/1,000 deliveries). Compared to the previous program, the tests with new parameters had improved screening performance. The triple and quadruple tests had detection rates of 65.2% and 72.7%, respectively, at a false-positive rate of 5%. The optimal cut-off value for the quadruple and triple tests was 1:250. We have presented a Korean-specific parameter set for Down syndrome screening. The proposed screening test using this parameter set may improve the performance of Down syndrome screening for Korean women.

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Section: Resultsmentioning

confidence: 96%

Section: Figmentioning

confidence: 99%

Korean-Specific Parameter Models for Calculating the Risk of Down Syndrome in the Second Trimester of Pregnancy

Kwon

Park

et al. 2011

J Korean Med Sci

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“…Serum screening has shown to be cost-effective for detecting Down syndrome (23 ) and can reduce the need for invasive amniocentesis (24,25 ). However, recent studies revealed poor accuracy and imprecision of RIA in measuring uE 3 compared with results obtained from liquid chromatographytandem mass spectrometry (LC-MS/MS) analyses, and poor agreement of uE 3 concentrations was observed between RIA and chemiluminescent immunoassay methods (26,27 ). More importantly, discrepancies in assay performance of various kits that cannot be normalized by applying multiples of the median (MoMs) could impact the accuracy of the risk estimation for Down syndrome (27)(28)(29)(30).…”

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confidence: 99%

“…Since 2000, chemiluminescent immunoassays have become commonly used in clinical laboratories in the US for uE 3 testing (26,27 ). This methodology has advantages over other immunoassays in that it is analytically more sensitive and testing can be carried out on an automated analyzer, therefore reducing human error.…”

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confidence: 99%

Measurement of Unconjugated Estriol in Serum by Liquid Chromatography–Tandem Mass Spectrometry and Assessment of the Accuracy of Chemiluminescent Immunoassays

et al. 2014

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BACKGROUND Unconjugated estriol (uE3) is routinely analyzed in clinical laboratories as risk assessment for Down syndrome. Immunoassays of various types are the most commonly used methods. The accuracies of RIAs and ELISAs for uE3 have been questioned, and to date there have been no independent studies investigating the accuracy of the relatively new chemiluminescent immunoassays. We developed and validated a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for uE3 measurements in serum. METHODS Serum samples from patients in the second trimester of pregnancy were used, and uE3 concentrations were measured by LC-MS/MS and the Beckman Coulter Access® 2 and Siemens IMMULITE 2000 automatic chemiluminescent immunoassay analyzers. RESULTS The LC-MS/MS method was validated and showed limit of detection 0.05 ng/mL; limit of quantification 0.2 ng/mL; linearity of response to 32 ng/mL; total imprecision of 16.2%, 10.4%, and 8.2% for uE3 at 1.10, 4.18, and 8.32 ng/mL, respectively; and analytical recoveries of 95.9%–104.2%. ANOVA of the correlation for LC-MS/MS results vs chemiluminescent immunoassays results showed R2 = 0.9678 (Access 2 = 0.9305 LC-MS/MS + 0.2177, Sy|x = 0.1786, P < 0.0001), and R2 = 0.9663 (IMMULITE 2000 = 0.8849 LC-MS/MS − 0.0403, Sy|x = 0.1738, P < 0.0001). Bland–Altman plots of uE3 results revealed concentration-dependent immunoassay biases. Mock risk analysis for Down syndrome showed no apparent difference in the risk assessment outcomes if the adjusted method-specific multiples of the median were used, and the assay imprecision was <10% CV. CONCLUSIONS Standardization of immunoassay methods for uE3 analysis is needed to improve the accuracy of the measurements.

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“…According to several authors, the effect of analytical variations of β-HCG, AFP and E3 tests on individual risk appears minor; however, some studies report that individual risks are sensitive to minor differences in analytical performances. 7,8 It has been shown that there may be a difference between β-hCG measurements in different analytical systems, especially as different standards are used or the measurement of nicked hCG and other hCG variants in serum affects the measurement. 9 In addition, Serdar et al reported that analytical variations have a great impact on second trimester risk estimation procedures and some articles have reported borderline cases as being problematic.…”

Section: Figurementioning

confidence: 99%

The Affect of Different Immunoassay Systems and Preanalytical Variables on Second Trimester Aneuploidy Screening Test Results

Öztürk¹,

Ozturk²,

Güçel³

et al. 2016

Turkiye Klinikleri J Med Sci

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A AB BS ST TR RA AC CT T O Ob bj je ec ct ti iv ve e: : Triple test is a screening test used in prenatal diagnosis of the disease that chromosomal defects such as Trisomy 18, 21 (Down syndrome) and neural tube defects (NTD). The objective of this study was to investigate the effects of sample storage conditions and different instruments on triple test individual risk results. M Ma at te er ri ia al l a an nd d M Me et th ho od ds s: : Serum samples were divided into four aliquots to measure alpha fetoprotein (AFP), beta human chorionic gonadotropin (β-hCG) and unconjugated Estriol (uE3). The one group of samples were measured on the same day, the other samples were then kept in the refrigerator (+4°C) and measured at Day 2 and at Day 7, in the deep freezer (-20°C) at Day 7 respectively. Each sample was individually measured in Beckman DXI 800 (Instrument 1) and Siemens IMMULITE 2000 (Instrument 2) Instruments, and MoM values and patient's individual risks were calculated for AFP, β-hCG and uE3 tests using PRA (Prenatal Risk Calculation, Benetech Software, Toronto) and PRISCA 4.0 (Prenatal Risk Calculation, TYPOLOG Software/GmBH, Hamburg, Germany) programs respectively. R Re es su ul lt ts s: : The difference between AFP MoM values was observed for the 1 st and 2 nd day of the 1st instrument (p <0.05). In comparison of day 1 st and 7 th day of measurement results differences were observed for AFP and β-hCG at +4°C and AFP and uE3 MoM values at -20°C. (p<0.05). The difference between AFP MoM values was observed for the 1 st and 2 nd day of the 2 nd instrument (p<0.05). When 1 st and 7 th day measurement results were compared, it was seen that there was a difference in uE3 and β-hCG MoM values in both the +4°C and -20°C pending samples (p<0.05). There was a significant difference (p<0.05) in MoM values of two Instruments, obtained from β-HCG, uE3 and AFP tests. Despite a significant difference in analytical variation, no significant differences were found between 2 instruments after evaluating patient's individual risks (p=0.58, p=0.59, p=0.33, p=0.65). C Co on nc cl lu us si io on n: : Waiting time for samples is a preanalytical variable that influences the individual risk results from triple test. For Down Syndrome, it is considered that different analytical performances have no effects on individual risk for patients whose individual risk is not near the limit value.

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Outcome Validation of the Beckman Coulter Access Analyzer in a Second-Trimester Down Syndrome Serum Screening Application

Cited by 21 publications

References 17 publications

Korean-Specific Parameter Models for Calculating the Risk of Down Syndrome in the Second Trimester of Pregnancy

Korean-Specific Parameter Models for Calculating the Risk of Down Syndrome in the Second Trimester of Pregnancy

Measurement of Unconjugated Estriol in Serum by Liquid Chromatography–Tandem Mass Spectrometry and Assessment of the Accuracy of Chemiluminescent Immunoassays

The Affect of Different Immunoassay Systems and Preanalytical Variables on Second Trimester Aneuploidy Screening Test Results

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