diff --git a/DESCRIPTION b/DESCRIPTION
index b490d8fb..0385902d 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: NMdata
 Type: Package
 Title: Preparation, Checking and Post-Processing Data for PK/PD Modeling
-Version: 0.1.8.941
+Version: 0.1.8.942
 Authors@R:
   c(person(given="Philip", family="Delff",email = "philip@delff.dk",role = c("aut", "cre")),
     person("Brian", "Reilly", email = "reilly.brian.m@gmail.com",role = c("ctb")),
diff --git a/R/addOmegaCorr.R b/R/addOmegaCorr.R
index c4bfb6bb..c0976b7a 100644
--- a/R/addOmegaCorr.R
+++ b/R/addOmegaCorr.R
@@ -1,5 +1,4 @@
 ##' add Omega correlations to a parameter table
-
 ##' @param pars A parameter table, like returned by `NMreadExt()`.
 ##' @param by The name of a column, as a string. Calculate the
 ##'     correlations within a grouping variable?  This will often be a
@@ -42,11 +41,30 @@ addOmegaCorr <- function(pars,by=NULL,as.fun,col.value="value"){
     res.list <- lapply(
         pars.list,
         function(x){
-            Sigma <- dt2mat(x[par.type=="OMEGA"],col.value=col.value)
-            mat.cor <- suppressWarnings(cov2cor(Sigma))
-            dt.cor <- mat2dt(mat.cor,triangle="all")
+
+            x.omega <- x[par.type=="OMEGA"]
+            dt.cor <- NULL
+            if(nrow(x.omega)){
+                Sigma <- dt2mat(x.omega,col.value=col.value)
+                mat.cor <- suppressWarnings(cov2cor(Sigma))
+                dt.cor.1 <- mat2dt(mat.cor,triangle="all",as.fun="data.table")[,par.type:="OMEGA"]
+                ##x <- mergeCheck(x,dt.cor[,.(par.type="OMEGA",i,j,corr=get(col.value))],by=cc(par.type,i,j),all.x=TRUE,quiet=TRUE)
+                dt.cor <- rbind(dt.cor,dt.cor.1)
+            }
             
-            x <- mergeCheck(x,dt.cor[,.(par.type="OMEGA",i,j,corr=get(col.value))],by=cc(par.type,i,j),all.x=TRUE)
+            x.sigma <- x[par.type=="SIGMA"]
+            if(nrow(x.sigma)){
+                Sigma <- dt2mat(x.sigma,col.value=col.value)
+                mat.cor <- suppressWarnings(cov2cor(Sigma))
+                dt.cor.1 <- mat2dt(mat.cor,triangle="all",as.fun="data.table")[,par.type:="SIGMA"]
+                ## x <- mergeCheck(x,dt.cor[,.(par.type="SIGMA",i,j,corr=get(col.value))],by=cc(par.type,i,j),all.x=TRUE,quiet=TRUE)
+                dt.cor <- rbind(dt.cor,dt.cor.1)
+            }
+            if(!is.null(dt.cor)){
+                dt.cor <- dt.cor[,.(par.type,i,j,corr=get(col.value))]
+                dt.cor[is.nan(corr),corr:=0]
+                x <- mergeCheck(x,dt.cor,by=cc(par.type,i,j),all.x=TRUE,quiet=TRUE)
+            }
             x
         })
     
diff --git a/man/NMreadSection.Rd b/man/NMreadSection.Rd
index be38cc48..8ff211cb 100644
--- a/man/NMreadSection.Rd
+++ b/man/NMreadSection.Rd
@@ -94,9 +94,9 @@ suitable for the results part too.
 }
 \section{Functions}{
 \itemize{
-\item \code{NMgetSection()}: Deprecated function name. Use NMreadSection.
-
+\item \code{NMgetSection}: Deprecated function name. Use NMreadSection.
 }}
+
 \examples{
 NMreadSection(system.file("examples/nonmem/xgxr001.lst", package="NMdata"),section="DATA")
 
diff --git a/tests/testthat/testReference/NMcheckData_22.rds b/tests/testthat/testReference/NMcheckData_22.rds
new file mode 100644
index 00000000..c5ff9a55
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diff --git a/tests/testthat/testReference/NMwriteSection_08.rds b/tests/testthat/testReference/NMwriteSection_08.rds
new file mode 100644
index 00000000..a051a46b
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diff --git a/tests/testthat/testReference/addOmegaCorr_01.rds b/tests/testthat/testReference/addOmegaCorr_01.rds
new file mode 100644
index 00000000..277b7f4f
Binary files /dev/null and b/tests/testthat/testReference/addOmegaCorr_01.rds differ
diff --git a/tests/testthat/testReference/compareCols_06.rds b/tests/testthat/testReference/compareCols_06.rds
new file mode 100644
index 00000000..548bfd57
Binary files /dev/null and b/tests/testthat/testReference/compareCols_06.rds differ
diff --git a/tests/testthat/test_addOmegaCorr.R b/tests/testthat/test_addOmegaCorr.R
new file mode 100644
index 00000000..9372400f
--- /dev/null
+++ b/tests/testthat/test_addOmegaCorr.R
@@ -0,0 +1,16 @@
+library(data.table)
+context("addOmegaCorr")
+
+test_that("basic",{
+
+    fileRef <- "testReference/addOmegaCorr_01.rds"
+    file.mod <- "testData/nonmem/xgxr022.mod"
+
+    ext <- NMreadExt(file.mod)
+
+    res1 <- addOmegaCorr(ext)
+
+    res1
+    expect_equal_to_reference(res1,fileRef)
+        
+})