What It Is and What It Looks Like
Digested blood, deposited where an insect rests rather than where it feeds. Not a solid dropping in the way people expect — it goes on as a liquid and dries.
- Very dark brown to black, not grey and not rust-coloured when dry
- Small — individual marks around half a millimetre to a millimetre
- Rounded rather than angular, as a drop dries
- It bleeds into fabric slightly, like ink on blotting paper, which gives the edges a soft look under magnification
- Clustered, in a seam, a joint or a corner — not spread evenly over a surface
On a light mattress it looks as though somebody has touched the fabric repeatedly with a fine felt tip. On timber it looks like a scatter of tiny ink dots along a joint.
The Smear Test
- Take a white cloth or a piece of kitchen roll, damp not wet
- Press it on the mark and hold it there for a second or two
- Draw it away sideways
Digested blood smears rust-brown or reddish. That is the confirmation. Dry dirt and soot brush off or leave a grey mark; mould does not smear rust-coloured; ink smears its own colour.
Do the test on one mark, not on all of them. The rest of the spotting is evidence somebody may need to see, and its distribution tells them how long this has been going on. One mark answers the question.
The Four Things It Gets Confused With
- Ordinary dirt and dust. Spread evenly rather than clustered, brushes off dry, does not smear rust-coloured
- Mould spotting on a mattress in a damp room. Grey-green rather than black, often in patches rather than lines, and it does not smear rust
- Flea dirt. Also digested blood and it also smears rust — but it is found in carpet pile, pet bedding and an animal's coat rather than in a mattress seam. Location separates them
- Ink or dye from a leaking pen, a transfer from bedding, or a printed label. Smears its own colour
What the Pattern Tells You
The distribution is worth as much as the finding.
- A tight cluster in one part of a seam: a harbourage, and probably the primary one
- Along the whole length of the piping: established, and the population has grown beyond one site
- On the frame and the divan as well: months rather than weeks
- At the skirting line: long-running, and the room is the job rather than the bed
- On the wall above the bed: the same, and worth checking behind anything hanging there
Old Spotting Versus New
Spotting persists indefinitely — it does not fade or wash out on its own — so a treated room can still show plenty of it. That makes it a record rather than a diagnosis on its own.
The way to tell is to clear the field: after a treatment, once you are told you can clean, get the seams properly clean. Anything that appears after that is new, and that is a far more useful signal than trying to judge the age of a mark.
Theale: Finding It Early
Early spotting is a handful of specks in one small area, and it is very easy to take for dirt — which is precisely what makes the smear test worth knowing. Ten seconds turns "probably nothing" into an answer.
Photograph it before you test it. The smear test damages the mark you use it on, and the photograph of spotting in place is worth having - particularly in a rented property, where it is what a report to a landlord should rest on.
Bed bugs in Theale? Pest Control Specialists Berkshire treats bed bugs from £220 for the first room. Bed Bug Treatments in Theale has the full detail, or call 0118 336 1366.