This table contains recommendations regarding the maximum interval between time of last known physical contact and time of biological sample collection. Collection of samples beyond these time intervals may be justified under exceptional circumstances after discussion with senior forensic medical practitioners. When doubt exists, practitioners are urged to err on the side of caution and collect samples. It is possible, but unlikely, that a positive result could be obtained beyond the recommended time intervals.

These recommendations are not intended to act as a substitute for informed decision-making around optimal timing for a forensic medical service and/or decisions around what samples should be collected.

These recommendations apply to normally active individuals.  Timeframes may be extended for bedridden/inactive persons, or deceased persons.

Informed consent must be obtained prior to sample collection. Information must also be provided to patients regarding how results of forensic analysis might be stored and used (including recording of DNA profiles on a Victoria Police DNA database).

Forensic analysis of samples may be performed for the purpose(s) of:

• Identification of spermatozoa
• Identification of seminal fluid /components
• Identification of foreign DNA, including mitochondrial DNA
• Other (e.g. blood type analysis, saliva, foreign substance such as lubricant, vaginal fluid)

Slides made from swabs are only required when looking for spermatozoa, not for saliva, other fluids or chemical substances.

A decision may reasonably be reached NOT to collect samples for forensic analysis if:

• The behaviour of the subject has reduced the likelihood that a probative result might be obtained, for example by showering, washing or wiping the sample site
• The relationship between the victim and suspect is such that the suspect’s DNA is likely to be on the victim as a result of non-criminal behaviour, for example household contact or routine child care activity
• During the time between the alleged criminal contact and sample collection, the subject has engaged in activities (such as sexual activity with another person) that might significantly contaminate the sample site

In circumstances where drainage of body fluids after the alleged assault might result in the presence of biological material at a site other than the site where it was initially deposited, consideration should be given to collection of samples at times beyond those recommended in the table. For example, drainage of seminal fluid from the vagina might occur for hours to days following unprotected penile-vaginal intercourse with ejaculation resulting in the presence of seminal fluid on the perineum.

Consider sampling visible signs of dried body fluids or stains, regardless of time since the alleged assault.

Collect underwear when fluids might have drained onto clothing or when genital skin (including penile skin) might have transferred DNA to clothing.

There is no upper time limit for collection of biological samples such as foreign hairs, foreign material such as ejaculate in hair, and objects such as condoms or stained (or possibly stained) clothing such as underwear.

Limited data exists in relation to collection times for forensic analysis of samples collected from prepubertal children. Currently available data suggests that the yield is low when samples are collected from prepubertal children more than 48 hours after the last known physical contact.

*Note: ensure water vials from within FMEKs are NOT used for the mouth rinse due to the possible trace presence of decontaminant agents. Use 10 ml 'water for injection' from hospital stock.  If ‘water for injection’ unavailable 10 ml of tap water may be used for the mouth rinse.

**Note; the forensic laboratory does not do histology or look for mucous membrane cells in these specimens. Analysis is limited to DNA or certain other substances such as amylase (if there was penile – oral penetration) 

This guideline will be reviewed annually. Due for review December 2019.