SP-10 vs LH vs HCG: What Each Fertility Test Shows & When to Use It
Clear, at-home guidance for couples planning pregnancy
Overview
Fertility testing can feel confusing at first—especially when different kits measure different things. This guide explains the three core at-home tests from RapidTest.co—SP-10 (male fertility), LH (ovulation), and HCG (pregnancy)—so you know exactly what each one tells you, the best time to use it, and how to combine them for the smoothest path to conception.
Together, these tests give couples a complete picture: SP-10 checks sperm concentration, LH pinpoints the most fertile days, and HCG confirms success after a missed period. Use them individually or as part of our Couples Fertility Bundle.
Key Differences at a Glance
| Test | Measures | Who Uses It | When to Use | Outcome |
|---|---|---|---|---|
| SP-10 (Male Fertility) | SP-10 sperm protein (correlates with sperm concentration) | Men | Any time; repeat every 2–3 months or before TTC* | Normal vs low sperm concentration indicator |
| LH (Ovulation) | Luteinising hormone surge (24–36h before ovulation) | Women | Daily around mid-cycle to catch the surge | Identifies most fertile window |
| HCG (Pregnancy) | Human chorionic gonadotropin (produced after implantation) | Women | From first missed period (or 10–14 DPO**) | Confirms pregnancy |
*TTC: Trying to conceive | **DPO: Days past ovulation
SP-10: The Male Fertility Check
What it shows: The SP-10 Male Fertility Test measures a sperm-specific protein linked to sperm concentration. Two lines indicate a normal (fertile-range) concentration; one line suggests the level may be below the fertile threshold.
When to use it: Any time—ideally before you start trying to conceive, and then every 2–3 months to track changes. Consider retesting after lifestyle adjustments (sleep, diet, exercise), and speak to a clinician if low results persist.
LH: Pinpoint the Fertile Window
What it shows: An LH surge happens 24–36 hours before ovulation. Testing daily around the middle of your cycle helps you identify the best days for intercourse when TTC.
When to use it: Start a few days before you expect ovulation. If your cycle is 28 days, begin around day 10 and test daily until you see two lines indicating an LH surge.
HCG: Confirming Pregnancy
What it shows: The HCG test detects the pregnancy hormone produced after implantation. It can confirm pregnancy from the first day of a missed period with over 99% accuracy.
When to use it: Test from your first missed period. If you test early and get a negative but your period doesn’t arrive, test again after 48 hours—HCG typically doubles every 48–72 hours in early pregnancy.
How to Combine SP-10, LH & HCG (Simple Timeline)
| Cycle Phase | What to Do | Why It Helps |
|---|---|---|
| Pre‑conception (Any time) | He uses SP-10 to check baseline. Adjust lifestyle if needed; retest in 2–3 months. | Confirms sperm concentration is in the fertile range before TTC. |
| Follicular (Cycle days ~7–12) | She starts daily LH testing before the expected surge. | Builds a pattern and avoids missing the surge window. |
| Ovulation window (Surge day & next day) | Have intercourse during the LH surge and the following 24–36 hours. | Times conception to the most fertile days. |
| Luteal phase (Post‑ovulation) | Wait for the first missed period. Avoid early testing anxiety. | Reduces false negatives and uncertainty. |
| Missed period | Use HCG test to confirm pregnancy. If negative, retest after 48 hours. | Provides early, reliable confirmation. |
Accuracy Tips
- Follow kit instructions closely; timing matters for all three tests.
- For LH strips, test around the same time daily and limit fluid intake 2 hours beforehand.
- For SP-10, observe abstinence guidelines in the leaflet before providing a sample.
- Store kits at room temperature and check expiry dates.
All RapidTest.co fertility kits are CE-marked and manufactured in ISO 13485-certified facilities. See Test Accuracy Standards.
Plan Together with the Couples Fertility Bundle
The easiest way to cover every stage is our Couples Fertility Bundle—SP-10 for him, LH for her, and HCG to confirm results. Private, fast, and affordable for couples at the start of their journey or those seeking extra reassurance.
FAQs
Do I need all three tests?
Not always—but using SP-10, LH, and HCG together gives the clearest, fastest path to answers: sperm concentration, ovulation timing, and pregnancy confirmation.
Can SP-10 be normal if LH and HCG are negative?
Yes. SP-10 assesses male fertility; LH/HCG relate to female timing and pregnancy. Normal SP-10 doesn’t guarantee immediate pregnancy—timing still matters.
How soon after an LH surge should we try?
The LH surge indicates ovulation within 24–36 hours—try the day of the surge and the following day.
When should we see a doctor?
If conception hasn’t happened after 6–12 months of timed attempts, or if SP-10 remains low or cycles are irregular, speak to your GP or a fertility specialist.