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Quality and risk management tools
the pellet in 1 ml of fresh medium. Spin again at 2000 rpm for 15 minutes and again aspirate and discard the supernatant. Repeat the washing cycle. Resuspend the final sperm pellet in a small volume of fresh medium and overlay with 0.6 ml fresh medium then allow to swim up for 30–60 minutes at 37 ◦ C in a CO2 incubator. Recover the upper 2/3 of the overlay and assess. Constructing the RCA The process map for sperm preparation is shown in Figure 7.5. It clearly illustrates the need to delve deeper until no further subordinate level processes remain because, in reality, the sperm preparation process actually comprises three separate processes. Only by having dissected the process to this level can the following comprehensive troubleshooting exercise be undertaken. The Contributory Factors and their classifications are listed in Table 7.5. Benchmark criteria are taken from the recommended method for using PureSperm density gradients as per the manufacturer’s package insert and previously published information. Conclusions of the RCA While the method might not seem to be too different from that used by many other labs, there are numerous factors within the sperm preparation protocol that can contribute to reduced yield in quantitative and/or qualitative terms. In many cases the individual variation might not cause a Figure 7.5
A process map for sperm preparation in IDEF0 format. The first panel shows the obligatory parent process map which is then broken down into sub-processes displayed in multiple, hierarchically linked process maps. Each map should have no more than 6 steps (although 9 could be used without breaking the formal numbering convention). The first map (second panel of Figure) shows the basic tasks involved in the process (steps 1 to 6), with step 2 being shown in greater detail in the third panel. The annotation “A2” outside the bottom right-hand corner of step 2 in the 6-step chart of process A-0 (its “node number”) shows that the box has been detailed as a “child” diagram (i.e. the third panel of the Figure). In diagram A2, steps 1 and 2 are identified as being displayed in greater detail in child diagrams A21 and A22 (the fourth and fifth panels of the Figure). For clarity, information concerning the controls and mechanisms have been omitted.