diff --git a/ShoulderCase/@SCaseIDParser/SCaseIDParser.m b/ShoulderCase/@SCaseIDParser/SCaseIDParser.m
index b7e569a..8b64631 100644
--- a/ShoulderCase/@SCaseIDParser/SCaseIDParser.m
+++ b/ShoulderCase/@SCaseIDParser/SCaseIDParser.m
@@ -1,80 +1,81 @@
 classdef SCaseIDParser < handle
 % Used to validate shoulder case ID.
 % Check the shoulder case type (first character of the ID).
 % Check the shoulder case number (last characters)
 %
 % Can give the shoulder case ID with filled digits.
 % This has been implemented to give ShoulderCase.id4c.
 
   properties (Access = private)
     maxDigits
     SCaseValidTypes
     rawID
   end
 
 
 
   methods
 
     function obj = SCaseIDParser(rawID)
       obj.rawID = rawID;
       assert(ischar(rawID),'Input argument must be a char array.');
 
       obj.maxDigits = ConfigFileExtractor.getVariable('maxSCaseIDDigits');
       assert(not(isempty(obj.maxDigits)),'maxDigits property is empty');
 
       obj.SCaseValidTypes = ConfigFileExtractor.getVariable('SCaseIDValidTypes');
       assert(not(isempty(obj.SCaseValidTypes)),'SCaseValidTypes property is empty');
     end
 
     function output = isValidID(obj)
       types = obj.SCaseValidTypes;
       maxDigits = obj.maxDigits;
       output = obj.SCaseIDHasTypesAndMaxDigits(types,maxDigits);
     end
 
     function output = isNormalCase(obj)
       types = 'N';
       maxDigits = obj.maxDigits;
       output = obj.SCaseIDHasTypesAndMaxDigits(types,maxDigits);
     end
 
     function output = isPathologicalCase(obj)
       types = 'P';
       maxDigits = obj.maxDigits;
       output = obj.SCaseIDHasTypesAndMaxDigits(types,maxDigits);
     end
 
     function output = getID(obj)
       output = obj.rawID;
     end
 
     function output = getIDWithNumberOfDigits(obj,size)
+      assert(obj.isValidID,'%s is not a valid ID.',obj.getID);
       type = obj.getCaseType;
       number = obj.getCaseNumber;
-      fillingZeros = repmat('0',1,size-length(type)-length(number));
+      fillingZeros = repmat('0',1,size-length(number));
       output = [type fillingZeros number];
     end
 
   end
 
 
   methods (Access = private)
 
     function output = SCaseIDHasTypesAndMaxDigits(obj,types,maxDigits)
-      expression = ['[' types ']\d{1,' num2str(maxDigits) '}'];
-      output = textMatchesExpression(obj.rawID,expression);
+      expression = ['^[' types ']\d{1,' num2str(maxDigits) '}$'];
+      output = obj.textMatchesExpression(obj.rawID,expression);
     end
 
     function output = getCaseType(obj)
       output = obj.rawID(1);
     end
 
     function output = getCaseNumber(obj)
       output = obj.rawID(2:end);
     end
 
   end
 
 
 end