diff --git a/R/get_cv.R b/R/get_cv.R
index afc3178e..67be6d7a 100644
--- a/R/get_cv.R
+++ b/R/get_cv.R
@@ -98,6 +98,11 @@ get_rse <- function (fmf, poped.db,
       eval(parse(text=paste(capture.output(default_args[[i]]),"<-",i)))
     }
   }
+
+  ## if prior is given in poped.db then add it to the given fim
+  if((!isempty(poped.db$settings$prior_fim) && all(size(poped.db$settings$prior_fim)==size(fmf)))){
+    fmf = fmf + poped.db$settings$prior_fim
+  }
   
   inv_fim <- tryCatch({
     inv(fmf,...)
diff --git a/tests/testthat/examples_fcn_doc/examples_evaluate.fim.R b/tests/testthat/examples_fcn_doc/examples_evaluate.fim.R
index a053212a..4b1d798d 100644
--- a/tests/testthat/examples_fcn_doc/examples_evaluate.fim.R
+++ b/tests/testthat/examples_fcn_doc/examples_evaluate.fim.R
@@ -69,3 +69,7 @@ FIM.7
 det(FIM.7)
 get_rse(FIM.7,poped.db,fim.calc.type=7)
 
+## evaluate FIM and rse with prior FIM.1
+poped.db.prior = create.poped.database(poped.db, prior_fim = FIM.1)
+FIM.1.prior <- evaluate.fim(poped.db.prior)
+FIM.1.prior
diff --git a/tests/testthat/test_evaluate.fim.R b/tests/testthat/test_evaluate.fim.R
index 5630d717..cf353218 100644
--- a/tests/testthat/test_evaluate.fim.R
+++ b/tests/testthat/test_evaluate.fim.R
@@ -9,7 +9,7 @@ test_that("RSE from evaluate.fim", {
   comp.red.1 <- get_rse(FIM.1,poped.db)
   comp.red.4 <- get_rse(FIM.4,poped.db,fim.calc.type=4)
   comp.full.0 <- get_rse(FIM.0,poped.db)
-  
+  comp.red.1.prior <- get_rse(FIM.1.prior, poped.db.prior)
   
   for(i in 1:length(expected.reduced)){
     expect_that(round(comp.red.1[[i]],digits=1), equals(expected.reduced[i], 
@@ -24,6 +24,8 @@ test_that("RSE from evaluate.fim", {
                                         tolerance = 0.01, scale = expected.reduced[i]))
   }
   
+  expect_true(all.equal(comp.red.1/sqrt(2), comp.red.1.prior))
+  
 })
 
 test_that("det(FIM) using evaluate.fim, approx and derivative types", {