A method of detecting a target microbiological entity in a sample, the method comprising the steps of: providing a first probe attached to first beads; placing said first beads in the sample so that any target microbiological entity attaches to said first probe; providing a second probe which also attaches to said target microbiological entity so that any of said target microbiological entity links said first and second probes; and a sensor detecting capacitance of beads and processing capacitance data to quantify target microbiological entity presence in the sample wherein, the first beads are magnetic or paramagnetic, application of a magnetic field causing said first beads to act as transport beads which convey second beads having the second probe attached and which are tethered to the first beads by the target microbiological entity, the method includes magnetically removing said tethered first and second beads, so that un-tethered second beads are isolated, and the sensor detects the number of second beads as being indicative of the amount of target microbiological entity, and in which: the tethered second beads are released from the first beads by heating before sensing, or the target microbiological entity includes nucleic acid, and wherein PNA probes complementary to those on the second beads or the first beads displace the nucleic acid due to preferential PNA-PNA binding to release the nucleic acid and so to release said tethered second beads from said first beads. providing a first probe attached to first beads; placing said first beads in the sample so that any target microbiological entity attaches to said first probe; providing a second probe which also attaches to said target microbiological entity so that any of said target microbiological entity links said first and second probes; and a sensor detecting capacitance of beads and processing capacitance data to quantify target microbiological entity presence in the sample wherein, the first beads are magnetic or paramagnetic, application of a magnetic field causing said first beads to act as transport beads which convey second beads having the second probe attached and which are tethered to the first beads by the target microbiological entity, the method includes magnetically removing said tethered first and second beads, so that un-tethered second beads are isolated, and the sensor detects the number of second beads as being indicative of the amount of target microbiological entity, and in which: the tethered second beads are released from the first beads by heating before sensing, or the target microbiological entity includes nucleic acid, and wherein PNA probes complementary to those on the second beads or the first beads displace the nucleic acid due to preferential PNA-PNA binding to release the nucleic acid and so to release said tethered second beads from said first beads. the tethered second beads are released from the first beads by heating before sensing, or the target microbiological entity includes nucleic acid, and wherein PNA probes complementary to those on the second beads or the first beads displace the nucleic acid due to preferential PNA-PNA binding to release the nucleic acid and so to release said tethered second beads from said first beads.