Abstract
Background
Total human chorionic gonadotropin (hCGt) tumour marker testing is regarded as an “off label” application for most commercial methods. We compared four assays in patients with a hCGt tumour marker request. We hypothesised that regression slopes would be altered and that outliers would be more common with tumour marker than with pregnancy samples if the detection of malignancy associated hCG molecular forms differed amongst assays. Further such systematic differences would be obvious and large enough to change clinical management decisions.
Results
We measured hCGt in 390 samples from 137 females and 253 males with a tumour marker request and 208 pregnancy controls with the following methods: Access Total βhCG, Architect Total-βhCG, Cobas hCG + β and Immulite HCG. The between method regressions determined on tumour marker and pregnancy samples were not significantly different. The outlier rates were similar for male and female tumour marker and the pregnancy groups: 1.6% (95% confidence interval [CI] 0%–3.1%), 2.2% (95% CI 0%–4.7%) and 2.9% (95% CI 0.6%–5.2%). The outliers were randomly distributed amongst the methods and we were confident that they would not adversely influence clinical decisions.
Conclusions
The hCGt results were clinically equivalent with no systematic difference amongst the four assays.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organisation(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
References
1. Stenman U, Alfthan H, Hotakainen K. Human chorionic gonadotropin in cancer. Clin Biochem 2004;37:549–61.10.1016/j.clinbiochem.2004.05.008Search in Google Scholar PubMed
2. Gronowski AM. Lumpers and splitters: the debate continues. Clin Chem 2018;64:1670.10.1373/clinchem.2018.294710Search in Google Scholar PubMed
3. Ferraro S, Trevisiol C, Gion M, Panteghini M. Human chorionic gonadotropin assays for testicular tumors: closing the gap between clinical and laboratory practice. Clin Chem 2018;64:270–8.10.1373/clinchem.2017.275263Search in Google Scholar PubMed
4. Cao Z, Rej R. Are laboratories reporting serum quantitative hCG results correctly? Clin Chem 2008;54:761–4.10.1373/clinchem.2007.098822Search in Google Scholar PubMed
5. Rinker AD, Tietz NW. β-hCG vs intact hCG assays in the detection of trophoblastic disease. Clin Chem 1989;35: 1799–800.10.1093/clinchem/35.8.1799Search in Google Scholar
6. Lempaiainen A, Hotakainen K, Blomqvist C, Alfthan H, Stenman U. Hyperglycosylated human chorionic gonadotropin in serum of testicular cancer patients. Clin Chem 2012;58:1123–9.10.1373/clinchem.2012.183723Search in Google Scholar PubMed
7. Cole LA, Du Toit S, Higgins TN. Total hCG tests. Clin Chim Acta 2011;412:2216–22.10.1016/j.cca.2011.08.006Search in Google Scholar PubMed
8. Whittington J, Fantz CR, Gronowski AM, McCudden C, Mullins R, Sokoll L, et al. The analytical specificity of human chorionic gonadotropin assays determined using WHO international reference reagents. Clin Chim Acta 2010;411:81–5.10.1016/j.cca.2009.10.009Search in Google Scholar PubMed
9. Greene DN, Petrie MS, Pyle AL, Kamer SM, Grenache DG. Performance characteristics of the Beckman Coulter total βHCG (5th IS) assay. Clin Chim Acta 2015;439:61–7.10.1016/j.cca.2014.09.029Search in Google Scholar PubMed
10. Ungerer JP, Pretorius CJ, Dimeski G, O’Rourke PK, Tyack SA. Falsely elevated troponin I results due to outliers indicate a lack of analytical robustness. Ann Clin Biochem 2010;47:242–7.10.1258/acb.2010.010012Search in Google Scholar PubMed
11. Altman DG, Machin D, Bryant TN, Gardner MJ. Statistics with confidence, 2nd ed. Chapter 6: proportions and their differences. UK: BMJ Books, 2000.Search in Google Scholar
12. Ungerer JP, Marquart L, O’Rourke PK, Wilgen U, Pretorius CJ. Concordance, variance, and outliers in 4 contemporary cardiac troponin assays: implications for harmonization. Clin Chem 2012;58:274–83.10.1373/clinchem.2011.175059Search in Google Scholar PubMed
©2020 Walter de Gruyter GmbH, Berlin/Boston
