A specimen collection and delivery apparatus for collecting clinical specimens and delivery of samples thereof to, e.g., microfluidic testing devices for diagnostic analysis is disclosed. The specimen collection and delivery apparatus includes a closure housing for coupling with a sample tube at one end, an open luer for coupling with a complementary luer on a microfluidic device at the other end, and a filter matrix disposed in the interior. The filter matrix is air permeable and liquid impermeable at atmospheric pressure and prevents sample from flowing through the open luer end when coupled to a sample tube containing a specimen. Under vacuum, the liquid sample fraction of the specimen can be drawn through the filter matrix and into the microfluidic testing device through the luer connection for diagnostic analysis.