Clarity Diagnostics hCG Single Step Combo Urine/Serum Cassette Pregnancy Test Kit DTG-COMBO (868025). Cassette Style. Sensitivity: 20 mlU/ml. Specificity: 100% - No cross reaction with FSH/TSH/LH. 99% Overall Accuracy. Can be used with urine or serum. 24 Month Dating. CLIA Waived for Urine Samples. CLIA Moderate for Serum Samples. 50/BX. Priced per box.