Clearblue offers a range of pregnancy tests, all of which detect the clinically proven urinary pregnancy marker – human chorionic gonadotrophin (hCG) to provide accurate and trusted results.
How hCG is used to detect pregnancy
The hormone hCG is produced in the earliest stages of pregnancy. During early pregnancy it plays a role in survival of the corpus luteum1 and has a significant role in the implantation of the blastocyst and protection of the embryo against immune attack at the fetal/maternal boundary. The hormone is initially produced by the embryo and therefore acts as a marker for its presence.2
Levels of hCG rise rapidly and predictably in the earliest days of pregnancy3 and it usually first appears in urine 9-10 days following the estimated day of conception when using the most sensitive laboratory assays.4 The levels of hCG in early pregnancy have also been found to be highly similar between women.3 This makes hCG an ideal urinary marker for quickly and accurately assessing whether a woman is pregnant or not.
Clearblue Pregnancy Tests can be used up to 4 days before the expected period (i.e. 5 days sooner than the day of the missed period ).
Published literature shows that hCG levels reach at least 50 milli-International Units per milliliter (mIU/ml) on the day a pregnant woman's period is expected.5-7 If a Clearblue Pregnancy Test is used on the day of the expected period, it is more than 99% accurate in detecting the presence of hCG.8 The high sensitivity of the Clearblue Pregnancy Test also means that pregnancy can be detected up to 4 days before the expected period. The graph below shows a typical rise in urinary hCG from the first detection of pregnancy.
Not all pregnant women who test before the day of their expected period will obtain a 'pregnant' result. This is because urinary hCG levels may not yet be above the threshold for the test.
All Clearblue Pregnancy Tests are rigorously tested using early pregnancy urine samples from women whose LH surge day is known and from which the day of expected period can be estimated.7 Using these samples Clearblue can assess the proportion of women expected to have sufficient hCG in their urine sample to generate a 'pregnant' result, on each specific post-conception day. If women choose to test early, the likelihood of detecting pregnancy before the day of the expected period is clearly displayed in the product packaging. Any woman who tests early and gets a negative result, but still suspects pregnancy, should test again on or after the day their period is expected.
Clearblue tests are over 99% accurate from the day of the expected period
HCG levels can vary between women, however, if a Clearblue Pregnancy Test is used from the day of the expected period, it is more than 99% accurate in detecting the presence of hCG.8 Circulating levels of hCG increase with age in women, particularly around the menopause, and it has been proposed that this may lead to false positive results with pregnancy testing kits, particularly for perimenopausal women.9 Clearblue Digital Pregnancy tests have been tested using urine panels from peri and postmenopausal cohorts. Using different ‘Lots’ of pregnancy test gave a false positive rate of between 0% and 0.3%. All positive results were for women who were over 50 years of age.10 At Clearblue we believe that consumers need a result they can be confident in, and therefore we provide products that deliver over 99% accuracy from the day of the expected period.
How hCG is used to estimate time since ovulation
The Clearblue Advanced Pregnancy Test with Weeks Estimator is the latest innovation in pregnancy testing. It is the FIRST and ONLY pregnancy test to provide an estimate of time since ovulation, for women testing pregnant. Clearblue Advanced Pregnancy Test with Weeks Estimator determines the level of hCG in urine to estimate weeks since ovulation. Pregnancy duration has been scientifically validated as being related to absolute quantities of hCG in urine7 and can be used to give an estimation of time since ovulation in weeks, relative to the surge in luteinizing hormone (LH). The result is displayed on an easy-to-read digital display, as ‘Not Pregnant’ or ‘Pregnant’ together with an estimate of weeks since ovulation (1-2, 2-3, 3+ weeks).
The Clearblue Advanced Pregnancy Test with Weeks Estimator gives the earliest estimate of time since ovulation. Traditionally, the date of the first day of the Last Menstrual Period (LMP) is used to determine pregnancy duration as this is often the only information available in early pregnancy. LMP is inaccurate as many women do not know, or are uncertain of the correct date11,12 and it is accurate to within one week in only 46% of women.13
The Clearblue Advanced Pregnancy Test with Weeks Estimator gives an estimate of time since ovulation relative to the LH surge.14 Agreement of the Weeks Estimator results with other clinical findings ranges widely from 45-99%, depending on the reference and analytical methods used.15
The Clearblue Advanced Pregnancy Test with Weeks Estimator is:
- Accurate - over 99% accurate in detecting pregnancy from the day of the expected period16
- Unique - the FIRST and ONLY pregnancy test that can estimate time since ovulation, for women testing pregnant
- Clinically proven - high level agreement with time since ovulation determined by LH surge14
- Sensitive - can be used up to 4 days before the expected period (5 days sooner than the day of the missed period)17
- Unmistakably clear - results displayed in words and numbers on a digital screen
- Reliable - based on established technology
- Simple to Use - convenient and easy to interpret
- Trustworthy- from Clearblue, the world’s #1 selling brand* in home pregnancy and fertility tests
Digital results for greater accuracy in consumers’ hands
The Clearblue Advanced Pregnancy Test with Weeks Estimator and the Clearblue DIGITAL Pregnancy Test contain an optical reader which provide clear digital results in words and thereby eliminate the human error that can occur when reading traditional line tests.17
The fully integrated Clearblue DIGITAL Pregnancy Test provides women with four important benefits:
- It confirms whether a woman is pregnant with 99% accuracy on the day of the expected period.18
- It is easy and convenient to use
- It is sensitive enough to be used up to 4 days before the expected period (5 days sooner than the day of the missed period) 19
- It provides a simple result in words: 'Pregnant' or 'Not Pregnant'.
Visual signs give consumers confidence
Over 25 years of consumer research has given Clearblue an exceptional understanding of our consumers’ needs, allowing us to develop the next step in visual home pregnancy tests. Not only is the Clearblue PLUS Pregnancy Test over 99% accurate at detecting pregnancy from the day of the expected period20, but it is also the easiest home pregnancy test to use.21 The innovative Clearblue PLUS Pregnancy Test offers six important benefits:
- It is over 99% accurate at detecting pregnancy from the day of the expected period20
- It has an ergonomically designed handle, making the Clearblue PLUS Pregnancy Test the easiest to use21
- It is sensitive enough to be used up to 4 days before the expected period22
- Its Color Change Tip helps women to perform the test more easily
- Its integrated Floodguard™ helps women to use the test correctly
- It provides an easy-to-read + or - result in just 3 minutes
*Based on international sales in nearly 20 countries compiled using independent market research
1 Baird DD, Weinberg CR, McConnaughey DR, Wilcox AJ. Rescue of the corpus luteum in human pregnancy. Biol Reprod 2003 Feb;68(2):448–56.
2 Perrier d'Hauterive S, Berndt S, Tsampalas M, Charlet-Renard C, Dubois M, Bourgain C, et al. Dialogue between blastocyst hCG and endometrial LH/hCG receptor: which role in implantation? Gynecol Obstet Invest 2007;64(3):156–60.
3 Nepomnaschy PA, Weinberg CR, Wilcox AJ, Baird DD. Urinary hCG patterns during the week following implantation. Hum Reprod 2008 Feb;23(2):271–7.
4 Wilcox AJ, Baird DD, Weinberg CR. Time of implantation of the conceptus and loss of pregnancy. N Engl J Med 1999 Jun 10;340(23):1796–9.
5 Lenton EA, Neal LM, Sulaiman R. Plasma concentrations of human chorionic gonadotrophin from the time of implantation until the second week of pregnancy. Fertil Steril 1982 Jun;37(6):773–8.
6 Chard T. Pregnancy tests: a review. Hum Reprod 1992 May;7(5):701–10
7 Johnson, SR., Miro, F, Barrett, S. & Ellis, JE . Levels of urinary human chorionic gonadotrophin (hCG) following conception and variability of menstrual cycle length in a cohort of women attempting to conceive. Curr Med Res Opin 2009 25: 741–748).
8 Data on file. Clearblue has been shown to be over 99% accurate from the day of the expected period when compared to a reference method in laboratory studies using urine samples supplied for pregnancy testing.
9 Snyder JA, Haymond S, Parvin CA, Gronowski AM, Grenache DG (2005) Diagnostic considerations in the measurement of human chorionic gonadotropin in aging women. Clin Chem 51, 1830-1835.
10 SPD data on file.
11 Geirsson RT, Busby-Earle RM. Br J Obstet Gynaecol. (1991) 98: 108–109.
12 Waller DK, et al, Cunningham GC. Paediatr Perinat Epidemiol. (2000) 14: 262–267.
13 Mustafa G, David RJ. Comparative accuracy of clinical estimate versus menstrual gestational age in computerized birth certificates. Public Health Reports. (2001) 116: 15–21.
14 Data on file.
15 Refer to pack insert
16 Johnson S, Perry P, Alonzo T, Zinaman M. Analytical Performance of Home Pregnancy test that estimates time since ovulation based on hCG threshold concentration at week boundaries. Clin Chem (2013) S209;B45
17 Tomlinson C, Marshall J, Ellis JE. Comparison of accuracy and certainty of results of six home pregnancy tests available over-the-counter. Curr Med Res Opin 2008 Jun;24(6):1645–9.
18 Data on file. When compared to a laboratory reference method, Clearblue Digital Pregnancy Test has been shown to be over 99% accurate from the day of the expected period when using urine samples supplied for pregnancy testing. Reference method used: Perkin Elmer AutoDELFIA hCG.
19 Data on file. Clearblue Digital Pregnancy Test can be used as early as 4 days before the period is expected. That's 5 days sooner than waiting for the missed period. The amount of pregnancy hormone increases rapidly in early pregnancy. In clinical testing, Clearblue Digital Pregnancy Test detected the pregnancy hormone in 51% of women when testing 4 days before their expected period, 82% at 3 days before their expected period, 90% at 2 days before their expected period and 95% at one day before their expected period.
20 When compared to a laboratory reference method, Clearblue PLUS Pregnancy Test has been shown to be over 99% accurate from the day of the expected period when using urine samples supplied for pregnancy testing. Reference method used: AutoDELFIA hCG (Perkin Elmer).
21 Data on file. In a US study of 149 women using leading line tests, over 80% of women found Clearblue PLUS the easiest to use in sampling.
22 Data on file. Clearblue recommends that women test from the day of the expected period. However, the pregnancy hormone increases rapidly in early pregnancy and Clearblue PLUS Pregnancy Test can be used to test up to 4 days before the expected period, which is 5 days sooner than waiting for the missed period. In clinical testing, Clearblue PLUS Pregnancy Test detected the pregnancy hormone in 56% of women when testing 4 days before their expected period, 88% at 3 days before their expected period, 97% at 2 days before their expected period, and 98% at 1 day before their expected period.
Always read full instruction leaflet of product before use. This material is intended for healthcare professionals only. It is for general information only with no warranties, representations or undertakings, express or implied, and does not constitute medical advice. It may refer to products not yet registered or approved in a given country. Please ask your local pharmacist or SPD contact for products available in your country. Product images are for illustration only. Clearblue is a trademark of SPD Swiss Precision Diagnostics GmbH (“SPD”). © 2013 SPD (except for any third party content identified as such). All rights reserved.