If a drop of blood is 0.05 mL, how many drops of blood are in a blood collection tube that holds 2 mL?
The correct answer and explanation is:
To determine how many drops of blood are in a 2 mL blood collection tube, given that one drop equals 0.05 mL, we use simple division: Number of drops=2 mL0.05 mL/drop=40 drops\text{Number of drops} = \frac{2\ \text{mL}}{0.05\ \text{mL/drop}} = 40\ \text{drops}
✅ Correct Answer: 40 drops
📘 Explanation (300 words):
In medical and laboratory settings, measurements of blood and other fluids are often given in milliliters (mL). A drop is a very small volume and for estimation purposes, it’s commonly accepted that 1 drop = 0.05 mL. This estimate is used when precision isn’t absolutely critical or when dealing with approximate measurements.
To determine how many such drops make up a 2 mL volume, we divide the total volume by the volume of one drop: 20.05=40\frac{2}{0.05} = 40
This means 40 individual drops, each of 0.05 mL, are needed to fill a 2 mL blood collection tube.
This type of calculation is helpful in clinical practice and laboratory procedures. For instance, when collecting blood using a finger prick or micro-sampling technique, technicians may only be able to collect small volumes at a time. Knowing the approximate volume of a drop helps them estimate how many drops they need to collect a desired volume of blood.
It is also useful for medication dosing, especially in pediatrics or with eye/ear drops, where precise small-volume administration is important.
However, it’s worth noting that the actual volume of a drop can vary slightly depending on the fluid’s viscosity and the device orifice (like the tip of a pipette or dropper). Despite this variability, 0.05 mL is a widely accepted average volume for a standard drop of blood.
In conclusion, when a blood collection tube holds 2 mL, and each drop is 0.05 mL, there are 40 drops of blood in the tube.