How many primers are used in the LAMP method?

The LAMP method uses 4 primers:  

1. Forward Inner Primer or FIP - The Forward Inner Primer consists of a F2 region at the 3'end. This region complements the F2c region of the template sequence. At the 5'end, the FIP consists of an F1c region, which is identical to the F1c region of the template sequence.

2. Forward Outer Primer or FOP - The Forward Outer Primer is shorter in length than the FIP. It also has a lower concentration. The F3 region of this primer is complementary to the F3c region of the template sequence. The Forward Outer Primer is also called the F3 Primer. 

3. Backward Inner Primer or BIP - The Backward Inner Primer consists of a B2 region at the 3'end, which is complementary to the B2c region of the template sequence. At the 5'end, the BIP consists of a B1c region, which is identical to the B1c region of the template sequence.

4. Backward Outer Primer or BOP - The Backward Outer Primer consists of a B3 region. This region is complementary to the B3c region of the template sequence. The Backward Outer Primer is also known as the B3 Primer.