Forensic Double Swab Kit

A Forensic Double Swab Kit is a standardized biological evidence collection package containing two swabs designed to be used sequentially on the same evidence area, maximizing the recovery of biological material — including blood, saliva, semen, touch DNA, and other cellular deposits — from surfaces where contact traces may be limited or unevenly distributed. The double swab technique improves DNA yield compared to single swab collection, particularly on porous, textured, or dry surfaces where cellular material adheres irregularly and a single swab pass fails to recover the full available sample.

The kit contains two sterile swabs — a wet swab and a dry swab used in sequence — along with individual packaging for each collected swab, a collection reference form, evidence tape, and tamper-evident sealing for chain of custody compliance. The first swab is moistened with sterile distilled water or a low-ionic-strength buffer before contact with the evidence surface, hydrating dried biological deposits to improve cellular transfer onto the swab fiber matrix. The second dry swab is applied immediately after the wet swab, collecting residual cellular material loosened by the moisture from the first pass and absorbing excess moisture that could promote microbial degradation of the DNA during storage and transport.

Swab tip materials include nylon flocked fiber, rayon, and cotton in various tip sizes — standard 1cm diameter tips for most surface applications and mini-tip variants for narrow grooves, threads, and tight access areas. Nylon flocked swabs release a higher percentage of collected cellular material during elution in extraction buffer compared to fiber-wound alternatives, improving DNA extraction efficiency and final template yield for profiling.

Each swab is individually packaged in a sterile peel-apart pouch, with the completed kit sealed in a labeled evidence bag with tamper-evident closures and chain of custody documentation fields printed on the outer packaging.

In Pakistan, forensic double swab kits are used by Federal Investigation Agency (FIA) forensic teams, provincial police crime scene units, Medico-Legal departments, and academic forensic science programs for biological evidence recovery from crime scenes, weapons, vehicles, and personal items.

Tactical Supply Pakistan supplies forensic double swab kits for law enforcement, judicial, and forensic laboratory procurement across Pakistan.