Innovation for reducing blood culture contamination: initial specimen diversion technique.

We hypothesized that diversion of the first milliliter of venipuncture blood-the initial specimen diversion technique (ISDT)-would eliminate incompletely sterilized fragments of skin from the culture specimen and significantly reduce our blood culture contamination rate (R). We studied our hypothesis prospectively beginning with our control culture (C) definition: one venipuncture with two sequentially obtained specimens, 10 ml each, the first specimen (M1) for aerobic and the second (M2) for anaerobic media. The test ISDT culture (D) was identical, with the exception that each was preceded by diverting a 1-ml sample (DS) from the same venipuncture. During the first of two sequential 9-month periods, we captured D versus C data (n=3,733), where DMXR and CMXR are R for D and C specimens. Our hypothesis predicted DS would divert soiled skin fragments from DM1, and therefore, CM1R would be significantly greater than DM1R. This was confirmed by CM1R (30/1,061 [2.8%]) less DM1R (37/2,672 [1.4%]; P=0.005), which equals 1.4%. For the second 9-month follow-up period, data were compiled for all cultures (n=4,143), where ADMXR is R for all (A) diversion specimens, enabling comparison to test ISDT. Our hypothesis predicted no significant differences for test ISDT versus all ISDT. This was confirmed by DM1R (37/2,672 [1.4%]) versus ADM1R (42/4,143 [1.0%]; P=0.17) and DM2R (21/2,672 [0.80%]) versus ADM2R (39/4,143 [0.94%]; P=0.50). We conclude that our hypothesis is valid: venipuncture needles soil blood culture specimens with unsterilized skin fragments and increase R, and ISDT significantly reduces R from venipuncture-obtained blood culture specimens.

Three- to six-year followup for 379 benign image-guided large-core needle biopsies of nonpalpable breast abnormalities.

BACKGROUND: Determining the negative predictive value of benign large-core needle biopsy of nonpalpable mammographically detected breast abnormalities has been difficult because benign results generally preclude surgical excision. Longterm followup of these patients is important to ensure timely diagnosis of new abnormalities and to identify false negatives. STUDY DESIGN: This cohort study comprised 379 patients, all with benign diagnoses following imaging-guided large-core needle biopsy of nonpalpable mammographically detected abnormalities. Mammographic, clinical, and laboratory records (when appropriate) were reviewed for all patients followed at our institution. For patients followed elsewhere, these data were provided by each patient's current primary-care physician after obtaining written informed consent from the patient. RESULTS: We obtained followup for 312 patients (82.3% of 379), for whom the mean followup period was 55 months; 67 patients were either lost to followup (44, 11.6%), had no followup by patient choice (18, 4.7%), or died of causes other than breast cancer (5, 1.3%). Of these 312 patients, we found only 1 (0.3%) false negative in which a 4-mm lesion was observed to have grown to approximately 11 mm eight months later, and was found to be an infiltrating ductal cancer at rebiopsy. The negative predictive value was calculated as 0.997 (311/312). Analysis of core histologies indicated the followup group was a representative sample. CONCLUSIONS: These data suggest that benign mammographically detected abnormalities can be diagnosed with a high level of confidence using image-guided large-core needle biopsy, and that mammographic or ultrasonographic screening or both at 6 and 12 months might be sufficient before returning the patient to routine screening mammography.