Different Re-centrifugation Conditions for Infectious Disease Screening Using the Abbott I2000.

We investigated whether an ordinary centrifuge can achieve the standard centrifugal effect required according to specifications for infectious disease screening using the Abbott i2000. Samples were collected and centrifuged following a standard operating procedure (SOP). They were then divided into three groups according to the results of the initial screening tests: a negative group, weak-positive group, and positive group. Twenty negative samples and all weak-positive and positive samples were re-analyzed. Two tubes for each re-analyzed sample were centrifuged simultaneously, one for 10 min at 10 000 × g, per recommendations, and one for 10 min at 2750 × g. No significant difference was found between the groups using different centrifugal forces. There was a strong correlation in the quantitative values between the two conditions of centrifugation. Consistency analysis showed a Cronbach's alpha > 0.8 for detection of Treponema pallidum, human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B surface antigen in the three groups (negative group, weak-positive group, and positive group) under different centrifugation conditions. Strong consistency was found under different centrifugal conditions, regardless of the initial testing results. In conclusion, we conducted centrifugation steps in duplicate, according to infectious disease screening protocols. Our study showed that all samples should be centrifuged using a recommended relative centrifugal force after a proper clotting time, as in the standard operating procedure of our laboratory. In this way, we were able to obtain the same results using an ordinary centrifuge as those obtained using a high-speed centrifuge, such as the Abbott i2000.