OBJECTIVES: New diagnostic approaches, including molecular profiling, have improved the ability to establish accurate diagnoses of hematologic cancers, but have also increased the complexity of test ordering, information integration and interpretation. This study examined the role of specialty and other laboratory providers, the types of diagnostic tests provided for patients with suspected hematologic cancers, and subsequent health care costs. METHODS:  Patients with bone marrow biopsies and suspected hematologic cancer/condition (2005- 2011) were identified from claims data from a large US health plan. Included patients had ≥6 pre- &  ≥3-months post-biopsy health plan coverage. Lab tests in the 30 days post-biopsy were identified. Patient cohorts were based upon laboratories performing marrow morphologic assessment/directing testing sequence:  Genoptix (GX, a specialty hematology-testing laboratory); large commercial laboratories (LL), other laboratories (OL); academic labs were excluded. Diagnostic/treatment medical costs (per-patient-per-month) during the 30-days & 1 year post-biopsy were examined (ANOVA). RESULTS: Of 30,393 patients with suspected hematologic malignancy/condition, 94.25% had marrow morphology reviewed. OL patients were slightly younger (58.19 OL vs. ,  59.88 GX, 59.39 LL, P<0.001). More flow cytometry was done at GX (96.68%) vs 87.68% in LL and 69.78% in OL.  Cytogenetics/FISH analysis rates were:  95.96% GX, 80.78% LL, 51.68% OL. Use of molecular diagnostics was less common (26.03% in GX, 14.27% in LL and 9.31% in OL). 1-year PPPM costs were $4487 GX, $4325 LL, and $5407 OL (P<0.001)); costs PPPM excluding the testing period were $2132 GX, $2686 LL, and $3341 OL (P<0.001). CONCLUSIONS:  Frequency of diagnostic tests in the 30-days post-biopsy varied, with complex tests conducted more frequently in the hematology specialty laboratory. However, disease-related costs with the specialty laboratory were lower than costs for some laboratories with lower use of these tests. Further exploration of the impact of alternative diagnostic testing approaches on costs and clinical outcomes is  warranted.