Abstract: Provided are compositions, including products of manufacture and kits, and methods, for predicting the successful construction of a genomic T-Cell Receptor (TCR) library from a tissue sample; or predicting the successful sequencing of a TCR sequence from a tissue sample, wherein optionally the tissue sample comprises or is derived from a biopsy or a Formalin-Fixation and Paraffin Embedding (FFPE) sample, and optionally the tissue sample is a human or an animal sample. In alternative embodiments, provided herein are assays for predicting successful library construction and sequencing of a TCR chain. In alternative embodiments, the T cell is a tumor infiltrating lymphocyte (TIL). The results of methods provided herein can generate a prediction as to the success of assays used for quantifying T-cells and sequencing T-cell receptors, including any commercially available assay (e.g., ImmunoSeq, Adaptive Biotechnologies, Seattle, Wash.) to effectively assess TCR quantity and clonality.