Table 3.
Analysis of blood samples for PCOS sub-study
| Test | Preservative | Instrument | Method principle |
| Testosterone | Lithium heparin | n/a | RIA (radioimmunoassay) |
| Sex-hormone binding globulin SHBG | Lithium heparin | n/a | IRMA (immunoradiometric assay) |
| Free androgen index (FAI) | N/A | Calculated | Calculated |
| Free testosterone | N/A | Calculated | Derived from mass equations |
| 17-hydroxyprogesterone (17-OHP)* | Lithium heparin | n/a | RIA (radioimmunoassay) |
| Prolactin* | Lithium heparin | Centaur | ICLMA (immunochemiluminometric assay) |
| Thyroid stimulating hormone (TSH)* | Lithium heparin | Centaur | ICLMA (immunochemiluminometric assay) |
* These additional tests were performed for women with oligomenorrhoea plus at least one of the following: a positive questionnaire response to a question on problems with acne; a positive questionnaire response to a question on problems with hair; or FAI of 5.5 nmol/L or more. Women were categorised as having oligomenorrhoea if they reported irregular menses or reported that their menstrual cycles were either less than 24 days long or 35 or more days long. (Women who were post-menopausal or had undergone a hysterectomy were excluded.) All women in this group are currently being followed up as part of the PCOS sub-study.