Thursday, October 19, 2017
Batching determines whether blood samples arrive in time as planned, or whether it is a matter of chance when they arrive. But how can we minimise batching of blood tests and ensure rapid response time?
Inside view of the Tempus Input Module on the GLP systems Track - seamless lab automation integration without batching.
As an example you are waiting for the bus to go to work. You arrived early and are the first to get into the bus. Other passengers pile in after you, and soon you are at the back of the bus. The friendly driver waits for one more passenger, who arrives at the last minute. So, when you finally come to your bus stop, you are the last out of the bus and the last to get to work. Hey, that's not fair!
But the example shows how batching affects processing time. The more passengers are batched in the bus, the longer the first person to board the bus has to wait. Transport time for each individual will vary, because it depends on how many are batched together.
As a result of batching, it is not possible to calculate a fixed maximum time when items are sent in batches. It is necessary to work with an average time instead.
Batching occurs when blood samples are sent off together in a capsule. There is no way of knowing for certain when the last samples have been collected and packed for dispatch. When the samples arrive, it is a matter of chance which will be analysed first. The transport time varies, and then everyone is forced to work with average times for blood sample analyses.
An alternative to sending batches of blood samples in a capsule is to use the Tempus600 system to send them. Here the samples are sent individually according to the FIFO principle – First In, First Out. FIFO means there is a fixed maximum transport time, which in turn means it is possible to calculate a fixed total turnaround time (ToTAT) for blood sample analysis.
E.g.
Taking the blood sample – 4 min
Cabin to machine – 2 min
Transport time – 1 min
Analysis time for blood samples, e.g. 20 min
Altogether 27 min.
Batching can occur at different stages in the process. It may happen before the samples are sent in the Tempus system.
Batching has a negative effect on response times, regardless of where in the system it occurs – with the lab technicians, from transport to dispatch, when trays are emptied, with centrifuging, or with response times. At any point, batching is a disadvantage.
That is why it is important to have procedures that eliminate or minimise batching. It is optimal, for example, to place the Tempus600 system as close to the cabins as possible, and at an equal distance from all cabins. That makes it easy for staff to send samples, and staff are less likely to batch samples before sending them.
Hospitals are beginning to make demands about response times, when they introduce a total solution from taking blood samples, through analysis, until the doctor receives the results of the blood test. They know the fixed maximum response time, and expect that the results of blood tests are delivered within the fixed interval of time.
The primary purpose behind faster response times is to be able to treat the patient as soon as possible. An early diagnosis means treatment can be started within a short time, and the patient can go home earlier.
It is an advantage when optimising the process to keep the patient in focus. Earlier, doctors probably received results twice a day, but now results are back, only a short time after the sample has been sent off. The sooner the doctor receives the test results, the sooner treatment can be started.
By minimising batching, the analytical equipment is used optimally. If blood samples are sent one at a time, they are also analysed one at a time, which evens out the load on the equipment. Turnaround time is optimised, and treatment can be started earlier.
Today, results of tests come continually to the doctor. If doctors cause batching themselves, and do not start treatment immediately after receiving test results, then they are not taking advantage of the FIFO (First In, First Out) principle.
Even when the best conveyor system is used, it is necessary to adapt procedures to minimise or avoid batching. Otherwise it is not possible to reap the advantages of fast analysis of samples, so it will still have a negative effect on response times.
When an integrated conveyor solution is introduced for analysing blood samples, the process changes from a series of sub-processes to a continuous whole. The new solutions mean the people operating the machines must adopt new thought patterns. They are now part of a production flow, and need to inform each other about what they are doing, because otherwise no one knows where the weak points are. Even though one end of the conveyor is functioning well, batching at the other end can delay results.
The disadvantage of a fully automated system is that it is never stronger than the weakest link. Even though the FIFO principle is applied all the way through, there must be emergency procedures if there is a breakdown at some point along the line. Here it is necessary to assess the risks, and to make sure there are emergency procedures if A, B or C should break down. Everyone must know the emergency procedures, and which procedure to follow if the normal flow is disrupted.
Regardless of where you are working with blood samples – from requisition to results of tests – when there is batching at one point, it affects the whole line. In the long run, it is a disadvantage for the patient and costs the hospital a lot of money, and that money is taken from other things.
From a welfare economic viewpoint, money can be saved by minimising batching of blood tests, apart from the fact that it reduces the waiting time and uncertainty for patients and relatives.
How does batching affect response times for blood samples?;
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