Disclosed are methods, materials and devices for approximating
blood volume in a fluid obtained from a subject, such as blood in a
biological fluid collected during a surgical procedure. In particular applications, methods of estimating
blood volume in a sample as part of a method for estimating
blood loss from a subject are provided. The methods provide for a much accelerated technique for determining
blood volume and / or packed
red blood cell units in a sample (within about 5-10 minutes). The method and devices (canisters) may include a
red blood cell (RBC) flocculant, such as polyDADMAC, and employ a formula that includes a value for an approximate blood
hematocrit, and an approximate
red blood cell packing ratio (“η”) for a collection container. A Blood Indicator Panel (BIP) is also disclosed that comprises a material and / or panel that may be placed alongside or on a collection device, the material and / or panel being suitable for inscribing / printing thereon a series of graduated markings calibrated to coincide with an approximate volume of blood and / or unit measure of packed red blood cells. The series of graduated markings correspond to a calculation of blood volume or red
blood cell volume in a fluid sample, for example, according to a defined formula. Pediatric (about 200 ml or 250 ml size container), adult human (about 1,000 ml-1,500 ml) and veterinary (about 500 ml-2,500 ml) methods of measurement are also disclosed. Methods for detecting blood and determining approximate blood volume in a sample (e.g., a fluid biological sample), and kits for performing the methods, are also provided.