First Response Faint Line: The Most Sensitive Test Explained
First Response Early Result can detect pregnancy earlier than most. Here's how to read faint lines.
Why First Response shows lines first
First Response Early Result (FRER) is the most sensitive home pregnancy test, detecting hCG as low as 6.3 mIU/mL. This means it can show a faint positive days before other tests—and days before your missed period.
FRER faint lines are common
Because FRER is so sensitive, faint lines are extremely common—especially when testing early. A squinter on FRER at 9-10 DPO often becomes a clear positive on other tests by 12-13 DPO.
The FRER indent issue
First Response tests do have visible indent lines where the test line appears. These can sometimes catch dye and look like a vvfl. The key: a real positive has definite pink color, while an indent is colorless.
How to read your FRER
Check your result at 3 minutes in good lighting. If there's a pink line—any pink line—that's hCG being detected. Use our scanner to enhance the image and confirm color is present.
FRER for progression tracking
Many women use FRER to track line progression because the lines darken noticeably as hCG rises. Our app lets you compare FRER photos side-by-side to see if your lines are getting stronger.
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