How to submit a sample, so the result stands up

A test is only as good as the sample it starts from, so most of what can go wrong goes wrong before the sample reaches the bench. Get these right and the number on your certificate is one nobody can argue with.

What to send. Every test line says what it needs — a litre of water in a sterile bottle, a full concrete cube, half a kilo of soil in a clean bag. Send the amount asked for; a short sample is one we may have to decline rather than guess with.

Keep it cold, keep it fast. Microbiology starts changing the moment a sample is taken. Water and food for micro should reach us within six hours, cold, in a cool box with an ice pack — not frozen. Chemistry and materials are more forgiving, but sooner is always better.

Label it so we cannot mix it up. On the container, not just the bag: what it is, where and when it was taken, and by whom. We start a chain of custody at the window, but it can only be as good as what arrives on the bottle.

The Tuesday run. We collect free across the Corporate Area and as far as Spanish Town every Tuesday, for anything already booked by the Monday. Outside that, a courier or a drop at the window any working morning.