How to clean up blood without leaving a trace

dc.description.abstractForensic investigation television shows such as police procedurals, rooted in both fact and fiction, have become an ever-popular staple of modern television in the last 20 years. The popularity of these shows has been blamed for generating higher expectations for forensic evidence by juries across America and may also have had the effect of inspiring criminals attempt to cover up their crimes by destroying potential evidence, particularly bloodstains. Luminol is a popular blood detection technique because it can be sprayed throughout an area in a dark room and will chemiluminesce when it interacts with hemoglobin. This chemiluminescence is a signal to investigators that latent blood may be located in that spot. Luminol’s specificity and sensitivity have long been studied. Luminol is a stable molecule that becomes oxidized when it comes in contact with an oxidant such as hydrogen peroxide and a catalyst. In this excited state, the molecule is unstable and forms 3-aminophthalate. This molecule produces light, and the luminescence slowly dies out as the molecule returns to its ground state. Chemicals that disrupt the luminol reaction can be considered interferents. These include cleaning agents, biological agents, foods, and drinks, among others. Compounds such as sodium hypochlorite, sodium percarbonate, and hydrogen peroxide are commonly used as primary cleaning products or as components in popular brands of household cleaners. Such multisurface cleaners, extra strength detergents or other chemicals are readily accessible to someone attempting to clean up a crime scene. Sodium hypochlorite, also known as bleach, has previously been found to cross react with luminol, generating a chemiluminescent reaction whether heme is present or not. Sodium percarbonate is also known as active oxygen and is used in detergents to improve their stain removing capabilities. It can affect the luminol and Bluestar® Forensic tests by causing a negative result, even in the presence of blood. Hydrogen peroxide is a common disinfectant and a necessary component of most presumptive blood tests, however, bulk quantities of it in the luminol reaction stop the reaction from proceeding. Antioxidants, found in many foods and drinks, can inhibit luminescence by preventing heme from being degraded, an important step in order for the luminol reaction to proceed. The purpose of this investigation is to evaluate the effectiveness of common cleaning agents for removing detectable traces of blood based on published studies. Additionally, an attempt was made to determine if cleaning agents completely remove blood or if they disrupt the luminol reaction when a negative luminol result is obtained. To supplement the literature, a limited experiment was carried out and preliminary data was obtained. This investigation finds that some cleaners interfere with the luminol reaction by altering one or more components in a way that prevents the reaction from fully proceeding, even when blood is still present.en_US

Whether you accidentally cut your finger while meal prepping, are dealing with period stains on sheets, or nicked your ankle while shaving, here's how to easily remove blood stains from fabric.

Table of Contents Show

How to Remove Blood Stains
What You Need
Instructions
Does bleach make blood untraceable?
Can luminol detect blood cleaned with hydrogen peroxide?
What do criminals use to clean blood?
Does peroxide remove blood traces?

No matter if the stained fabric is a white blouse, linen sheet, or bath towel, first check the care label to make sure the item can be hand-washed and check the recommended water temperature. Because blood is a protein stain, use cold water when tackling the stain (hot water may actually help set the stain). Before you begin, test each cleaning method in an inconspicuous spot first, such as along the inside hem of a shirt, to make sure it won't discolor the fabric.

Follow the steps below to remove blood stains for good, and once the stain is gone, toss machine-washable items into the laundry. Double-check that the stain is fully removed before throwing it into the dryer. Your shirt (or sheets or towels) will look good as new.

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How to Remove Blood Stains

What You Need

Hydrogen peroxide
Paper towel or clean cloth
Mild dishwashing liquid
Ammonia
Baking soda
Soft toothbrush

Instructions

1. Test hydrogen peroxide in an inconspicuous spot first to make sure it won't discolor the fabric. Splash the blood stain with hydrogen peroxide, then let sit for a few minutes. Dab with a clean cloth, working from the outside of the stain inward.

2. Repeat if necessary. Once the stain is removed, launder the fabric.

3. If the stain is still there, try this: Apply a couple drops of dishwashing liquid to the stain and gently rub. Splash with ammonia (test a small spot first), then sprinkle with baking soda and let sit for a few minutes.

4. Using a toothbrush, gently scrub the stain in a circular motion until it disappears. Rinse with cool water. Launder the fabric.

Warning

Don't put the fabric in the dryer until the blood stain is completely removed. Otherwise, the dryer's heat will cause the remaining stain to set.

Does bleach make blood untraceable?

Chlorine-based bleaches are known to make bloodstains invisible, but applying chemicals such as luminol or phenolphthalein will still reveal the presence of haemoglobin – crucial for identifying blood – even after up to 10 washes.

Can luminol detect blood cleaned with hydrogen peroxide?

Luminol is often combined with hydrogen peroxide to react with the heme groups in blood, producing a bright blue glow, known as chemiluminescence. This glow allows crime scene technicians to detect blood that has dried on surfaces or to detect blood that someone tried to clean from a surface.

What do criminals use to clean blood?

The oxy cleaners even go beyond getting rid of visible stains. Usually detectives' gear can find traces of blood that are invisible to the naked eye. But these oxy cleaners make even the invisible traces of blood unrecognizable to the most common blood-detecting tests.