diff --git a/R/interpolate.conc.R b/R/interpolate.conc.R
index b313cf3f..918ca942 100644
--- a/R/interpolate.conc.R
+++ b/R/interpolate.conc.R
@@ -276,8 +276,8 @@ extrapolate.conc <- function(conc, time, time.out,
     if (auc.type %in% "aucinf") {
       # If AUCinf is requested, extrapolate using the half-life
       ret <- extrapolate_conc_lambdaz(clast=clast, lambda.z=lambda.z, tlast=tlast, time_out=time.out)
-    } else if (auc.type %in% "auclast" |
-                 (auc.type %in% "aucall" &
+    } else if (auc.type %in% "auclast" ||
+                 (auc.type %in% "aucall" &&
                     tlast == max(data$time))) {
       # If AUClast is requested or AUCall is requested and there are
       # no BLQ at the end, we are already certain that we are after
diff --git a/R/sparse.R b/R/sparse.R
index eaad17e5..7a59f2cc 100644
--- a/R/sparse.R
+++ b/R/sparse.R
@@ -9,7 +9,7 @@
 #' @family Sparse Methods
 #' @export
 as_sparse_pk <- function(conc, time, subject) {
-  if (is.data.frame(conc) & missing(time) & missing(subject)) {
+  if (is.data.frame(conc) && missing(time) && missing(subject)) {
     time <- conc$time
     subject <- conc$subject
     conc <- conc$conc