In direct ELISAs, approximately 50% cross-reactivity with recombinant mouse IGFBP-4 is observed, and less than 1% cross-reactivity with recombinant human (rh) IGFBP-1, rhIGFBP-2, rhIGFBP-3, rhIGFBP-5 and rhIGFBP-6 is observed. Reconstitute at 0.2 mg/mL i