An insert for a sample collection tube includes a generally hollow tubular body insertable into the sample collection tube. The tubular body is open at least at one end. The tubular body of the insert has an internal cross-sectional area dimensioned to accommodate a width of test strip which comprises a plurality of test areas arranged along its length. The internal cross-sectional area of the tubular body is further dimensioned such that volume of 2.5 mL of a liquid sample inside the insert occupies a height which is at least sufficient to wet all of the test areas of the test strip when the strip is inserted lengthwise into insert containing the liquid sample.