A microfluidic check valve (164, 264, 400), comprising: a body comprising: a first outer surface; a second outer surface axially spaced from the first outer surface along a valve axis orthogonal to the first outer surface and the second outer surface; a first inside surface; a second inside surface axially spaced from the first inside surface; and a lateral surface disposed between the first inside surface and the second inside surface and surrounding the valve axis, wherein the first inside surface, the second inside surface, and the lateral surface define an internal chamber; an inlet bore formed through the body from the first outer surface and communicating with the internal chamber; an outlet bore formed through the body from the second outer surface and communicating with the internal chamber; a plurality of bosses disposed on the second inside surface, wherein the bosses are spaced from each other, allowing fluid to flow around and between the bosses; and a floating disk disposed in the internal chamber and freely movable between an open position and a closed position in response to a pressure differential between the inlet bore and the outlet bore, wherein: at the open position, the disk contacts the bosses and establishes a fluid flow path from the inlet bore, through the internal chamber including between adjacent bosses, and to the outlet bore; and at the closed position, the disk contacts the first inside surface and blocks fluid flow from the inlet bore into the internal chamber. a body comprising: a first outer surface; a second outer surface axially spaced from the first outer surface along a valve axis orthogonal to the first outer surface and the second outer surface; a first inside surface; a second inside surface axially spaced from the first inside surface; and a lateral surface disposed between the first inside surface and the second inside surface and surrounding the valve axis, wherein the first inside surface, the second inside surface, and the lateral surface define an internal chamber; a first outer surface; a second outer surface axially spaced from the first outer surface along a valve axis orthogonal to the first outer surface and the second outer surface; a first inside surface; a second inside surface axially spaced from the first inside surface; and a lateral surface disposed between the first inside surface and the second inside surface and surrounding the valve axis, wherein the first inside surface, the second inside surface, and the lateral surface define an internal chamber; an inlet bore formed through the body from the first outer surface and communicating with the internal chamber; an outlet bore formed through the body from the second outer surface and communicating with the internal chamber; a plurality of bosses disposed on the second inside surface, wherein the bosses are spaced from each other, allowing fluid to flow around and between the bosses; and a floating disk disposed in the internal chamber and freely movable between an open position and a closed position in response to a pressure differential between the inlet bore and the outlet bore, wherein: at the open position, the disk contacts the bosses and establishes a fluid flow path from the inlet bore, through the internal chamber including between adjacent bosses, and to the outlet bore; and at the closed position, the disk contacts the first inside surface and blocks fluid flow from the inlet bore into the internal chamber.