Yes its faulty / or not had enough sample. It happens. For what seems like incredibly simple technology they are actually quite sensitive to all sorts of little things inside the plastic housing. So whilst it might be you didn’t add enough sample, similar issues can happen if the pads inside aren’t making good contact, or a little bit of the plastic wasn’t moulded right to get the flow properly. The failure rate from defects rather than user error is low but does happen. If you are making millions of tests a week, as cheaply as possible some failures are probably unavoidable.
Back in 2005 I had the joy of recalling an entire batch of tests because the glue that sticks the bits all together inside started to fail a month after assembly and about 1/20 did exactly this!
@Edukator
I know that, but if there had been a distinct red line at T it would have been positive, with or without the control. It might not be valid but it gives you an accurate result all the same once it’s flowed past T. Obviously do it again to be sure.
No! The control line confirms that sufficient sample has flowed along the test to make the control line system operate correctly. If you didn’t add enough sample to get that to happen you can draw no conclusions about the meaning of anything (pos or neg) at the test line zone. With the right circumstances you could get a positive sample to show no test line if the flow is wrong OR a negative sample to show a test line because insufficient sample has washed the excess reagent off. One of the dangers of letting the public do these tests themselves is they make their own mind up what this means!
Poopscoop – if you don’t normally report the tests via the NHS website – they would probably be even more grateful if you could report this (they call it a Void) – as they will want to know the % failure rate.