labresults with the same labresultoffset

[yongfanbeta]

@tompollard when I selected some variables from lab table, found out there are several different lab results with the same labresultoffset, it means different values in the same time? how can it be!

for example, patientunitstayid = 245087 and labresultoffset = 11, there are two different ph values.

[alistairewj]

It appears the labs were revised at a later time.

Here is a query that shows the issue you are raising, multiple distinct lab results at the same time:

select labname, labresultoffset
, count(labresult) as num_labs
, count(distinct labresult) as num_distinct_labs
from lab 
where patientunitstayid = 245087 
and labresultoffset = 11 
group by labname, labresultoffset
order by labname;

labname	labresultoffset	num_labs	num_distinct_labs
Base Excess	11	2	2
FiO2	11	1	1
HCO3	11	2	2
O2 Sat (%)	11	2	2
paCO2	11	2	2
paO2	11	2	2
PEEP	11	1	1
pH	11	2	2
Respiratory Rate	11	1	1
Temperature	11	2	2
TV	11	1	1

When we add labresultrevisedoffset, which tracks the last change made to a lab, there are no longer two distinct labs at the same time.

select labname, labresultoffset, labresultrevisedoffset
, count(labresult) as num_labs
, count(distinct labresult) as num_distinct_labs
from lab 
where patientunitstayid = 245087 
and labresultoffset = 11 
group by labname, labresultoffset, labresultrevisedoffset
order by labname;

labname	labresultoffset	labresultrevisedoffset	num_labs	num_distinct_labs
Base Excess	11	52	1	1
Base Excess	11	78	1	1
FiO2	11	79	1	1
HCO3	11	52	1	1
HCO3	11	78	1	1
O2 Sat (%)	11	52	1	1
O2 Sat (%)	11	78	1	1
paCO2	11	52	1	1
paCO2	11	78	1	1
paO2	11	52	1	1
paO2	11	78	1	1
PEEP	11	79	1	1
pH	11	52	1	1
pH	11	78	1	1
Respiratory Rate	11	79	1	1
Temperature	11	52	1	1
Temperature	11	79	1	1
TV	11	79	1	1

[yongfanbeta]

thanks @alistairewj if I only use labresultrevisedoffset as our time to find variables, it exists same problem. for example, patientunitstayid = 141233 and labresultrevisedoffset = 1675. So if I want to find variables done in the same time, both labresultoffset and labresultrevisedoffset should be the same? I can't understand it, why two time?

[alistairewj]

Life is never easy!

Details on the columns are available here: http://eicu-crd.mit.edu/eicutables/lab/

Many reasons why labs could be entered at the same time. For example, they could be doing an arterial/mixed venous measurement at the same time to calculate oxygen consumption. More than that we can't tell you and you should consult with a domain expert.