A cartridge-housing system comprising an assay cartridge for use in a molecular diagnostics assay and a support housing for holding the assay cartridge ; the assay cartridge comprising: an assay region ; a first end comprising a first engagement member for engaging with the support housing ; and a second end comprising a second engagement member for engaging with the support housing ; wherein the second engagement member comprises a clip , the clip being formed by a resilient element extending from the second end of the cartridge and a fastening element extending from said resilient element; wherein the clip comprises a release element extending from the resilient element actuatable to release the clip from a support housing in use, wherein the first engagement member comprises a lip , the lip being formed by a protrusion extending upwardly from the upper surface of the first end of the cartridge ; wherein the support housing comprises: a first cooperating member configured to engage with the lip ; and a second cooperating member configured to engage with the clip ; wherein the support housing comprises a channel for receiving the cartridge ; wherein the first cooperating member is provided at one end of the channel and the second cooperating member is provided at the other end of the channel , wherein the first cooperating member comprises a first recess for receiving the lip of the cartridge , wherein the second cooperating member comprises an abutment element and a second recess . an assay region ; a first end comprising a first engagement member for engaging with the support housing ; and a second end comprising a second engagement member for engaging with the support housing ; wherein the second engagement member comprises a clip , the clip being formed by a resilient element extending from the second end of the cartridge and a fastening element extending from said resilient element; wherein the clip comprises a release element extending from the resilient element actuatable to release the clip from a support housing in use, wherein the first engagement member comprises a lip , the lip being formed by a protrusion extending upwardly from the upper surface of the first end of the cartridge ; wherein the support housing comprises: a first cooperating member configured to engage with the lip ; and a second cooperating member configured to engage with the clip ; wherein the support housing comprises a channel for receiving the cartridge ; wherein the first cooperating member is provided at one end of the channel and the second cooperating member is provided at the other end of the channel , wherein the first cooperating member comprises a first recess for receiving the lip of the cartridge , wherein the second cooperating member comprises an abutment element and a second recess . a first cooperating member configured to engage with the lip ; and a second cooperating member configured to engage with the clip ; wherein the support housing comprises a channel for receiving the cartridge ; wherein the first cooperating member is provided at one end of the channel and the second cooperating member is provided at the other end of the channel , wherein the first cooperating member comprises a first recess for receiving the lip of the cartridge , wherein the second cooperating member comprises an abutment element and a second recess . <EOS>