Application of thrombolytic drugs on clotted blood and bone marrow specimens to generate usable cells for cytogenetic analyses

Context.-Clotted blood and bone marrow specimens account for a large proportion of failed cytogenetic studies. There are no published protocols describing salvage of clotted specimens such that conventional chromosome or fluorescence in situ hybridization (FISH) studies can be performed. Objective.-To evaluate the utility of thrombolytic drugs on clotted blood samples to yield intact cells suitable for cytogenetic analysis. Design.-Five commercially available thrombolytic drugs (alteplase, urokinase, streptokinase, tenecteplase, reteplase) were evaluated in a series of blinded experiments to identify the best drug for lysing clots to produce samples suitable for chromosome and FISH studies. After the selection of alteplase as the drug yielding the most promising results, a comparative study between alteplase (0.75 mg/ml) and a commercially available anticlotting reagent (ACR) was performed. For each sample, mitotic index, chromosome length, and quality of slides prepared for conventional chromosome and FISH analyses were evaluated. Results.-Alteplase-treated samples produced a higher mitotic index than those treated with ACR while showing equivalent quality in conventional chromosome and FISH studies. We have demonstrated the utility of treating clotted blood samples with alteplase before cell culture to yield cells suitable for cytogenetic analysis. Since clinical implementation, this technique has been applied to more than 250 bone marrow samples, with a 93% success rate. Conclusions.-We believe the routine use of alteplase on clotted blood and bone marrow specimens should become standard for cytogenetics laboratories and may have similar utility in salvaging clotted specimens for other clinical assays requiring intact cells for analysis.