Background: The aim of the study was to determine the accuracy of home pregnancy tests (HPTs) in detecting human chorionic gonadotrophin (hCG) in human female urine and consumer certainty in reading the results. The Clearblue Digital Pregnancy Test (CBDPT) was compared with five alternative over-the-counter (OTC) brands of HPT.
Methods: HPTs (CBDPT [SPD, Geneva, Switzerland], Answer [Church & Dwight, Princeton, NJ], Predictor [Omega Teknika, Dublin, Ireland], Clearblue (non-digital) [SPD], EPT [McNeill, Fort Washington, PA], First Response [Church & Dwight]) were tested by study co-ordinators on samples of pooled urine containing hCG at 0 IU/l (negative control) or 25 IU/l (positive standard, typical of level found in early pregnancy), in a coded, randomised scheme. Results and level of certainty about the results were interpreted by 120 female volunteers.
Results: The CBDPT detected hCG in the 25 IU/l positive urine with 100% accuracy when read by volunteers. Accuracy of four alternative HPTs ranged from 65.8 to 87.5%, but was only 8.3% with the fifth test, Predictor. CBDPT was statistically significantly better than any of the alternative brands. All volunteers (100%) rated the results with the CBDPT as 'very certain' or 'certain' (score 1 or 2), whereas a score of 1 or 2 was recorded by only 40.3-58.3% for the other brands, except Predictor which was scored with certainty by 87.5%, although volunteers interpreted the result for the positive standard as not pregnant. A certainty score of 1 or 2 was recorded by a significantly (p<0.001) greater proportion of volunteers with CBDPT than any of the other HPTs.
Conclusions: The CBDPT was significantly better in terms of accuracy and certainty than non-digital OTC HPTs tested at a low hCG concentration. These results demonstrate that a digital reading offers significant benefits to the consumer over traditional non-digital tests.