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 In response to a need in forensic nursing practice the Forensic Blue Swabs™ was created to rid your exam room of the messy bottles of Toluidine Blue Dye (TBD) that get spilled and most of the time disposed of before you can use even half of the bottle. The National Forensic Nursing Insitute, Inc. has spent the past two years working on the design of the perfect solution to this practice problem. The Forensic Blue Swabs consists of a soft foam tipped swab with a shaft that contains 1% Toluidine Blue Dye Aqueous Solution. Just squeeze the shaft and the solution is soaked into the swab and ready for application.

In the genital assessment of sexual assault patients the TBD can be used to identify abrasions not seen by the naked eye and sometimes even with the use of a colposcope. There is about 2 milliliters of TBD in each swab which is more than enough for this application. It is important to have forensic protocol that ensures proper timing of the application of TBD. The Forensic Blue Swab should be used after external evidence collection and before the speculum examination in females.

Toluidine Blue Dye

 In the living patient, forensic nursing practice is based on the medical/forensic examination. After obtaining a patient history the nurses primary responsibility is to identify trauma on the head to toe assessment and the detailed genital assessment. There are a number of techniques and equipment available to assist in the identification of trauma for the forensic nurse to use as part of their diagnostic toolbox.

 One well studied method of identifying microtrauma in the genital area of sexual assault patients includes the use of Toluidine Blue Dye (TBD)., a nuclear stain. When placed on an area of skin where the epidermal layer (non-nucleated cells) has been removed, the underlying cells will uptake dye. This provides the forensic nurse the ability to see abrasion injury that the naked eye, and sometimes even by magnified examination will fail to identify.

Background of TBD Use

Lauber and Souma (1982) were the first to introduce research in this new technique. Recognizing that the technique required very little skill to apply the dye or detect microtrauma of the genitalia, they noted a significant difference between those that reported sexual assault and those that had consensual intercourse in regards to injury “positive” with TBD application. Regardless of the ability to determine consent, the most important benefit from TBD is the ability to identify the microtrauma caused by blunt force trauma to the genitalia. Furthermore, in the late 1980’s McCauley, et. al performed several controlled studies on pediatric, adolescent, and adult patients where TBD was used to identify micro-tears or abrasions, especially in the posterior fourchette, that is a common site of trauma from intercourse. Positive results with TBD does not determine whether the injury occurred from consensual or non-consensual intercourse. It can however bear witness that there has been blunt force trauma applied to the area in question.

TBD Application


oluidine Blue Dye application can be quick and easy. In the past, only large quantities (100ml) or more of TBD with short shelf lives were obtainable. This has led to large amounts of the solution being thrown away, or spilled in the course of preparing for application. Another difficulty with large quantities is contamination by using a multi-dose container to hold the solution. With the advent of the Forensic Blue Swabs made by the National Forensic Nursing Institute, pre-filled single patient use swabs can be used for applying the dye to the patients genital area.


  1. Collect all external genital specimens as indicated by examination prior to TBD application and consider photo documentation.
  2. Prior to speculum examination or instrumentation to area, apply TBD (1% aqueous solution) by using a Forensic Blue Swabs or a sterile cotton swab to genital area in question (avoid insertion of dye into vaginal vault). Dye application may be used on the labia majora, labia minora, posterior fourchette, perineal body and perianal area.
  3. Allow to dry for approximately one minute.
  4. Using spray bottle of 1% Acetic Acid, gently, with broad spray, flood the area until excess TBD is flushed away. Another method is to use a water soluble lubricant to remove excess stain.
  5. Gently blot the area with 4 x 4's. DO NOT rub the area.
  6. Consider photo documentation of area following TBD application.

What About DNA?

As Hochmeister, et. al described in 1997, application of TBD and 1% acetic acid directly to vaginal secretions did not alter the ability to perform RFLP or PCR on the specimens. \


 Bays, J., & Lewman, L. V. (1992). Toluidine blue in the detection at autopsy of perineal and anal lacerations in victims of sexual abuse. Arch Pathol Lab Med, 116(6), 620-21.

Hochmeister, M.N., Whelan, M., Borer, U.V., Gehrig, C., Binda, S., Berzlanovich, A., Rauch, E., Dirnhofer, R. (1997). Effects of toluidine blue and destaining reagents used in sexual assault examinations on the ability to obtain DNA profiles from postcoital vaginal swabs. Journal of Forensic Science, 42(2):316-319.

Jones, J.S., Dunnuck, C., Rossman, L., Wynn, B.N., Nelson-Horan, C., (2004). Significance of toluidine blue positive findings after speculum examination for sexual assault. American Journal of Emergency Medicine, 22(3):201-203.

Jones, J. S., Rossman, L., Hartman, M., & Alexander, C. C. (2003). Anogenital injuries in adolescents after consensual sexual intercourse. Acad Emerg Med, 10(12), 1378-83.

Lauber, A.A., Souma, M.L. (1982) Use of toluidine blue for documentation of traumatic intercourse. Obstetrics and Gynecology, 60(5):644-648.

McCauley, J., Gorman, R.L., Guzinski, G. (1986). Toluidine blue in the detection of perineal lacerations in pediatric and adolescent sexual abuse victims. Pediatrics, 78(6):1039-1043.

McCauley, J., Guzinski, G., Welch, R., Gorman, R., Osmers, F. (1987). Toluidine blue in the corroboration of rape in the adult victim. American Journal of Emergency Medicine, 5(2):105-108.

Micromedex, Inc., Vol. 95: Tolonium-Toxicologic Managements

Slaughter, L., Brown, C.R., Crowley, S., Peck, R. (1997). Patterns of genital injury in female sexual assault victims. American Journal of Obstetrics and Gynecology,176(3):609-616.