Index Share

How to read an OPK


Reading and recording an Ovulation Predictor Kit test

Sometimes people charting their fertility signs struggle to read their OPKs, occasionally to the point of increasing their stress unduly. The purpose of this article is to help alleviate this concern and to show how fertility charting can provide a great framework for this issue.

OPK Basics

This article focuses on the standard OPK where you read a test by comparing the intensity of a test line with the control line. These tests are both cheap and widely available and provide valuable information with regard to your cycle phase.

An OPK when positive, is calibrated to detect the Luteinizing Hormone (LH) surge which usually occurs just before ovulation. For details on how OPKs work and the relationship between your hormonal profile and the test result please check our in-depth OPK article.

Reading The Test

The test in general comes with instructions on how it should be performed and the timing for reading the result. Make sure to respect the instructions just to be certain that the test is valid.

On a practical level, the test is considered positive when the test line is darker or as dark as the control line. That may seem a simple enough criterion but in reality we see many people struggling with that and occasionally over analyzing the test.

Example of negative OPK test:

Example of positive OPK test:

Because of the timing between the LH surge and ovulation and the LH profile variability you do not need to be extremely accurate in reading the test. If the test line looks as dark, darker (or close enough for your eyes to not see the difference) to the control line, the test is positive. The exact value is not important because everyone is different.

In particular, you do not have to detect the darkest shade of the OPK. It has no particular meaning because the ovulation process starts when the LH levels start increasing. Consequently, it is not important to detect what some people call a Peak OPK or a “blazer”. It is not as significant as simply being positive for the purpose of determining your ovulation or your fertile phase.

Reading the Test Through an App

Some people find comfort in letting an App read the test for them using their phone camera. Although that is certainly convenient, it may give you a false sense of accuracy. In particular, Apps that provide detailed numerical values sometimes present incorrectly as LH levels. It may also introduce errors due to lighting conditions and other camera artifacts. As mentioned above, it should be rather easy to read the test. If it is not that means that either the test is invalid or you may be trying to get more info than the test can provide. In summary, trust yourself, fertility charting is accessible to all with or without technology.

OPK Related Data Entry Fields

Fertility Friend includes default data entry fields as well as optional fields to record multiple OPKs, the line intensity and if you are using a quantitative test or blood test, the LH level.

Optional Test Entries:

To add optional fields to your data entry form, tap the floating customize button (Gear icon) on the data entry screen and select Add Optional Tests.

Fertility charting to the rescue

The interesting feature of fertility charting is that it allows you to gain information from multiple fertility signs. This allows you to build a robust picture of your fertility instead of relying on a particular sign (being an OPK or another sign…). We recommend that you check, in addition to your OPK, your BBT (Basal Body Temperature) and your CM (Cervical fluid). With these 3 pieces of data you can build a surprisingly accurate picture of your cycle even if each individual sign is not observed with 100% accuracy. In other words just read your OPK with your own eyes and make a judgment call on the test without thinking it has to be 100% accurate. It should be immediate and without second guessing it.

Fertility Friend has been designed for this. Fertility Friend algorithms have the ability to impartially analyze your data without putting a subjective weight on one sign or another. Fertility Friend is designed not to replace you but to enhance your ability to see your patterns. You have the best knowledge of your own body.

Index Share

Get it on Apple App Store Get it on Google Play world Web App


© Tamtris Web Services Inc. Follow @fertilityfriend
Terms Of Service || Privacy Policy || Contact