diff --git a/Project.toml b/Project.toml
index 606d87e..2f636b8 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "DICOM"
 uuid = "a26e6606-dd52-5f6a-a97f-4f611373d757"
-version = "0.10.0"
+version = "0.10.1"
 
 [compat]
 julia = "0.7, 1"
diff --git a/src/DICOM.jl b/src/DICOM.jl
index cfcc45a..64bf64a 100644
--- a/src/DICOM.jl
+++ b/src/DICOM.jl
@@ -136,8 +136,12 @@ function find_dicom_files(dir)
 end
 
 function isdicom(file)
-    bytes = read(file, 132)[end-3:end]
-    String(bytes) == "DICM"
+    all_bytes = read(file, 132)
+    if length(all_bytes) < 132
+        return false
+    end
+    my_bytes = all_bytes[end-3:end]
+    return String(my_bytes) == "DICM"
 end
 
 function dcmdir_parse(dir; kwargs...)
diff --git a/test/runtests.jl b/test/runtests.jl
index 4fe4acb..42fd148 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -226,9 +226,21 @@ end
 @testset "Parse entire folder" begin
     # Following files have missing preamble and won't be parsed
     # ["OT_Implicit_Little_Headless.dcm", "CT_Implicit_Little_Headless_Retired.dcm"]
+    # along with an invalid notdicom.dcm file which we will first create 
+    notdicomfile = joinpath(data_folder, "notdicom.dcm")
+    open(notdicomfile, "w") do io
+      print(io, "!")
+    end
+    
+    # First, test the isdicom() function
+    fileDX = download_dicom("DX_Implicit_Little_Interleaved.dcm")
+    @test DICOM.isdicom(fileDX) == true
+    @test DICOM.isdicom(notdicomfile) == false
+
+    # Second, test if all valid dicom file can be parsed
     dcms = dcmdir_parse(data_folder)
     @test issorted([dcm[tag"Instance Number"] for dcm in dcms])
-    @test length(dcms) == length(readdir(data_folder)) - 2 # -2 because of note above
+    @test length(dcms) == length(readdir(data_folder)) - 3 # -3 because of note above
 end
 
 @testset "Test tag macro" begin