Introduction
The samples are stored in the freezer for preservation and may be taken out for processing , pathology tests, distributing, shipping etc. Freeze thaw cycle is the count that denotes number of times the sample was frozen and thawed (brought to room temperature)and different tests. This might result in the sample being frozen and thawed multiple times. Tracking this is very essential to decide the quality of the sample. The higher the number of freeze thaw cycles get, the quality of the samples decreases. ‘Increment Freeze/Thaw Cycles’ is a field configured at the child specimen level, that helps to increase the freeze thaw cycle of the child and parent sample
In OpenSpecimen, ‘Freeze/Thaw Cycles’ can be tracked during:
Creation of parent and child specimens
Creation of frozen and thaw event
Tracking ‘Freeze/Thaw Cycles’ during specimen creation
By default, when specimens are created, the value for ‘Freeze/Thaw Cycles’ is zero for primary specimens. If user wants to set value for this field, it can be edited on the single specimen page:
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When unplanned derivative or aliquots specimens are created, freeze/thaw cycle of parent is incremented by one and the child’s freeze/thaw cycle will be set to ‘parent value + 1’.
JSON Configuration
If user does not want freeze/thaw cycle to be incremented automatically, admin can configure to include these fields during child creation. For more details on configuration of this via JSON, refer to https://openspecimen.atlassian.net/wiki/x/NQB7Fw
Tracking ‘Freeze/Thaw Cycles’ in events
There are 2 events that capture the freeze/thaw of the samples - ‘Frozen Event’ and ‘Thaw Event’. The frozen and thaw event have the ‘Increment Freeze/Thaw Cycles’ field as shown in below screenshot. If user clicks on ‘Increment Freeze/Thaw Cycles’ when adding the frozen event then the freeze thaw cycle number is increased , it will increase the value for that specimen by 1.
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Default behaviour of the freeze thaw (FT) cycles field
When the parent specimen does not have a freeze thaw count specified, then the derived sample gets freeze thaw count as 1 on creation, i.e parent FT+1. The aliquot samples created get FT count as 2. So parent FT=1, derived =2 and child =2
If the parent freeze thaw is it set to 1, the child samples will be parent FT+1 and so on
JSON configuration