You use different tables in data step and  proc report. You use quotes instead of quoting functions. You dont use delimiters with the %scan and countw functions You manipulate the &i variable in the loop. You do not delete the labtabs table at the end of each loop May be this code will solve the problem. %macro CreateLabTab(paramlist,headerlist);   /* Declaring of local used variables */   %local i param header count Nobs;   /* Quoting of Parameters */   %let paramlist  = %BQuote(&paramlist.);   %let headerlist = %BQuote(&headerlist.);   /* Sorting the data into temporary tables */   Proc sort data = data1 out = work._T_&sysmacroname.1; by pt; run;   Proc sort data = data2 out = work._T_&sysmacroname.2; by pt; run;   /* Counting the number of loops , defining the space as delimiter */   %let count = %sysfunc(countw(&paramlist., %str( )));   %do i = 1 %to &count.;   /* Initialize the number of obs in the resulting dataset */     %let Nobs   = 0;     /* Splitting the parameterlists with delimiter and showing the results to the log */     %let param  = %scan(&paramlist. , &i, %str( ));     %let header = %scan(&headerlist., &i, %str(,));     %put;     %put %Str(Parameter  &i.);     %put %str(  Param : &param.);     %put %str(  Header: &header.);     /* Numbering the tables (or creating a third temporary table and deleting at the end of the loop) */     data labtabs&i.;       retain nobs 0;       merge _T_&sysmacroname.1 _T_&sysmacroname.2 end=done;       by pt;       /* Standardization of the texts with upcase, count the number of hits and output*/       if Upcase(LPARM) = Upcase("&param") then do;         Nobs + 1;         *********FLUFF******;         output;       end;       /* saving the number of obs in the resulting Dataset */       if done then call symputx("Nobs",Nobs);     run;     /* Generate report */     %if &Nobs. > 0 %then %do;       proc report nowd data=labtabs&i. headline headskip split='/';         column ('Patient' idvar) ("Title" groupnum) ("&header" time, (lvalue))  dummy;         define idvar/ group order = data left '';         define groupnum/group order = data center '';         define time/across center '' order = data;         define lvalue/ center '';         define dummy/ noprint;       run;     %end; /* end of %if &Nobs. > 0 */     %else %do;       %put NOTE: Dataset Labtabs&i. has no data;       %put NOTE: Do not generate report;     %end; /* end of %else case from %if &Nobs. > 0 */   %end;   /* end of %do i = 1 %to &count. */   /* deleting the temporary tables */   proc datasets nolist nodetails;     delete _T_&sysmacroname.1 _T_&sysmacroname.2;     run;   quit; %mend; %let paramlist = ALK_PHOS_SER  AST_SGOT_SER; %let headerlist=Alkaline phosphatase (U/L),ALT (mg/dL); %CreateLabTab(&paramlist.,%bquote(&headerlist.)); ... View more

Here is some sample data. In the original graph you saw, there are 3 groups of patients, with each patient measured up to 7 time points. Here is data from one group, which includes 3 patients. PT Time Value 102 1 1.1 102 2 1.1 102 3 1.2 102 4 1.3 102 5 1.3 102 6 1.2 103 1 0.7 103 2 0.7 103 3 0.6 103 4 0.9 103 5 0.7 103 6 0.8 104 1 0.9 104 2 0.9 104 3 0.8 104 4 0.9 104 5 0.9 104 6 0.9 ... View more

proc sort data=input;by id left right; run; data want; set input; by id left right; retain temp_entry; if first.left then temp_entry=entry; if last.left and last.right then do;     entry=temp_entry;     output; end; drop temp_entry; run; ... View more

JohnPura sorry about my earlier untested code (with bug) The line GROUP BY 1 HAVING varnum = MAX( varnum ) should not use that GROUP BY I have tested data and process, like LIBNAME YOUR (WORK) ; DATA DATA ; INPUT ObsN 3. (Cat1  Cat2   Cat3)( :$5. ) ; LIST;CARDS; 1      1      0      0 2      0      1      0 3      0      1      0 4      1      1      1 5      1      0      1 ; %LET your_data = YOUR.DATA ; %LET VARLIST = CAT1 CAT2 ; PROC SQL NOPRINT ; SELECT  name INTO :final_name separated by '/' from ( select name        FROM dictionary.columns        WHERE libname = "%UPCASE(%SCAN(&your_data,1,.))"           AND memname = "%UPCASE(%SCAN(&your_data,-1,.))"        having varnum=max(varnum)      /* fixing error on earlier*/    ) QUIT ; * put data into combo order ; PROC SORT DATA = &your_data OUT= ordered ;; BY _CHARACTER_ ; RUN ; * assign variable COMBO_REF unique for each combination of the character variables ; DATA combos_flagged ; SET ordered ; BY _CHARACTER_ ; combo_ref + FIRST.&final_name ; RUN ; The code is structured to avoid having to specify any column names. ... View more