Influence of Age and Needle Gauge on Bone Marrow Biopsy Specimen Adequacy.

Introduction. The quality and length of bone marrow biopsy core specimens should facilitate accurate diagnositic interpretation of marrow histopathology. A 11G specimen of length 1.6 cm or greater is considered adequate for pathologic evaluation by some authors. The length of specimens recovered with 11G needles appears to depend on needle design. We explored the possibility that the adequacy of bone marrow biopsy specimens may be influenced by patient age and the gauge of biopsy needles.

Methods. 88 bone marrow core specimens were recovered from 72 patients using 11G SNARECOIL bone marrow biopsy needles. The mean age of these patients was 61.4 and the m/f ratio was 45/27. The clinical diagnoses were isolated anemia, cytopenias, leukemia, lymphoma, myeloma and other in 18.0%, 33.3%, 13.8%, 13.8%, 5.5% and 15.2% of the patients, respectively. 10 patients underwent multiple procedures (2–6) for evaluation of treatment efficacy. 106 patients underwent 127 bone marrow biopsy procedures using 8G SNARECOIL needles. The m/f ratio was 56/50 and the mean age of the patients was 63.1years. The clinical diagnoses were isolated anemia, cytopenia, leukemia, lymphoma, myeloma or other in 22.2%, 19.6%, 14.9%, 21.2%, 12.5% and 9.4% patients respectively. 13 patients underwent multiple procedures (range 2–4) for evaluation of response to treatment.

Results. Although the mean length of the 11G and 8G specimens were statistically significantly the same (mean±SEM, 1.97±0.07 cm vs. 1.99±0.05 cm, respectively, p = 0.8), the distribution of specimen lengths was asymmetric or skewed for the 11G specimens (skewness(skw) =0.52) and nearly normal for the 8G specimens (skw =0.04). The deviation from a normal distribution suggested additional variable(s) might be effecting specimen length. The possible influence of age on specimen length relative to needle gauge was considered. The mean age of the patients biopsied with 11G needles was 61.4. The m/f ratios of the patients ≤64 and ≥65 were statistically the same (27/12 vs. 18/15, respectively, p = 0.2). The mean age of the patients biopsied with 8G needles was 63.1. The m/f ratios of the patients ≤64 and ≥65 were statistically the same (30/26 vs. 26/23, respectively, p =0.5). 11 G specimens from younger patients, ≤64, were more frequently adequate (1.6 cm or greater) (39/53 = 73.5%) than specimens from older patients ≥ 65 (18/35 = 51.4%), p = 0.03. Conversely adequate 8G specimens were recovered as frequently in older patients ≥65 years (40/55 = 72.7%) as they were in younger patients ≤64 years, (59/72 = 81.9%) p = 0.21. Moreover, in older patients, adequate biopsy specimens were recovered more frequently by 8G needles then by 11G needles (40/55=72.7% vs. 18/35 = 51.4%, respectively, p = 0.04).

Conclusions. 1. Age influences the rate of recovery of adequate bone marrow core biopsy specimens. 2. 8G needles recover adequate specimens more frequently than 11G needles in older patients.