| Diagnosis criteria |
1 | GTN may be diagnosed when the plateau of human chorionic gonadotropin (HCG) lasts for four measurements over a period of 3 weeks or longer; that is, days 1, 7, 14, 21. |
2 | GTN may be diagnosed when there is a rise of HCG of three weekly consecutive measurements or longer, over at least a period of 2 weeks or more; days 1, 7, 14. |
3 | GTN is diagnosed when the HCG level remains elevated for 6 months or more. |
4 | GTN is diagnosed if there is a histologic diagnosis of choriocarcinoma. |