Different Decimal Places For Different Laboratory Tests PharmaSug 2004, TT01 A. Cecilia Mauldin

What is a Lab? What can be a problem? Different ways of solving the problem The data for these examples The PUTN function When should we be careful Calculating the width and number of decimal places The variable that is formatting is calculated Creating a table of laboratory results Final thoughts References Different Decimal Places for Different Lab Tests

What is a Lab? Laboratory Test Laboratory Result HCT PLT RDW WBC

What is a lab? A Lab Mix

What Can Be a Problem? When reporting results for listings, we do not need to format. We should present the data as it is received. Unless we want to present all the lab results from the same test with the same format But when doing tables, how many decimals should each laboratory test have for the mean? For the standard deviation?

Different Ways of Solving the Problem Every Lab test will use the same format All will have best. or best.2? All will have 10.2 We put as many “IF” statements as there are Lab tests We use select statements We use a macro variable for each test …

Different Ways of Solving the Problem We Use the values from a modified version of the LabNormal dataset or another dataset where the width and number of decimal places for each test is given and use the PUTN function.

The Modified LabNormal Dataset Lab Test Low Normal Value High Normal Values Created Format HCT PLT RDW WBC

The Data for this Examples data new; input LAB $ result ; cards; HCT HCT PLT PLT PLT RDW RDW RDW RDW WBC 4.0 WBC ; run; data useinfor; input lab $ frstf $ low high ; cards; HCT PLT RDW WBC ; run;

The Data for this Examples (both datasets were already sorted by lab); data toprint; merge new useinfor; by lab; run; proc print data=toprint; by lab; id lab; run;

LAB result frstf low high HCT PLT RDW WBC The Data for this Examples We did not select a format for the RESULT variable. SAS is using 7.3 (or 22.3) as the best way to print the results.

The PUTN Function title "Using PUTN with a format variable that already exists"; data firste; set toprint; formatm = putn( result, frstf); label formatm="FORMATM: value with format given by FRSTF" ; run;

The PUTN Function Using PUTN with a format variable that already exists FORMATM: value with format given LAB result frstf by FRSTF HCT PLT RDW WBC

The PUTN Function The PUTN Function’s structure is: NewVar=PUTN(Nres, FMT, width1, deci); Where: NRES is an existing Numeric Variable. In this example RESULT. FMT is an existing Character variable. In this example FRSTF. It has to be character because values that are acceptable are date., ddmmyy10., time5. … WIDTH1 is an Optional Numeric variable with final width of NewVar. DECI is an Optional Numeric variable with number of decimals included in NewVar

The Variable That Is Formatting Is Calculated The format of the output variable can depend on the value of the numeric result. If the result is smaller than the Normal Lower Limit (NLL) we will increase the number of decimals, if the result is bigger than the Normal Upper Limit (NUL) we will increase the width.

The Variable That Is Formatting Is Calculated title2 "Second Example"; title3 "the variable that is formatting is calculated"; data seconde; set toprint; if result< low then meanf=putn(result,put(input(frstf,best.) + 0.1,best.)); else if result>high then meanf=putn(result,put(input(frstf,best.) + 1.0,best.)); run;

The Variable That Is Formatting Is Calculated Second Example the variable that is formating is calculated LAB result low high frstf meanf HCT PLT Smaller than the LLV RDW WBC If you want to show 3 decimal places for , you need to have 6.3 Did you mean to round? Who decided rounding for you?

When representing data: Find the maximum number of decimals in each lab test. Decide Rounding and number of decimal presented depending in the number of decimals in your data.

Creating a Table of Lab Results The table that we want has: The Laboratory Lab Test, The Mean and Standard deviation for each test. The Mean is going to have one more decimal place than the maximum number of decimals reported by the lab.

Creating a Table of Lab Results The Standard Deviation is going to have two more decimal places than the maximum number of decimals reported by the lab.

Creating a Table of Lab Results Rounding should be done before any formatting takes place. This will help search for values with too many decimals or not enough decimal values. Time for an advertisement for Proc SQL.

Calculating the Width and Number of Decimal Places PROC SQL; CREATE TABLE LABS AS SELECT DISTINCT LAB, result, PUT(result,BEST.) AS CHAR FROM new ORDER BY lab ; The dataset LABS has the new variable CHAR, from where we can search for a decimal place and we can calculate the number of decimal places in each observation. CHAR HAS ALL THE DECIMAL PLACES IN RESULT.

Calculating the Width and Number of Decimal Places PROC SQL; CREATE TABLE DECIMAL AS SELECT DISTINCT LAB, MAX(LENGTH(CHAR)- INDEX(CHAR,'.')) AS DECIMAL FROM LABS WHERE CHAR LIKE '%.%' GROUP BY LAB ; SELECT * FROM DECIMAL; The dataset Decimal is the equivalent of our LabNormal dataset, there is one record for each Lab test with the maximum number of decimals for that test

Calculating the Width and Number of Decimal Places The Variable that will format is calculated LAB DECIMAL HCT 3 PLT 3 RDW 5 WBC 3

Calculating the Width and Number of Decimal Places CREATE TABLE DECIMAL AS SELECT DISTINCT LAB, DECIMAL, 10**(-DECIMAL -1) FORMAT BEST. AS ONERND, 10**(-DECIMAL -2) FORMAT BEST. AS TWORND, "32." ||PUT(DECIMAL +1,1.) AS ONEFMT, "32." ||PUT(DECIMAL +2,1.) AS TWOFMT FROM DECIMAL ; SELECT * FROM DECIMAL; QUIT;

Calculating the Width and Number of Decimal Places OneFMT is the value that has the maximum number of decimals plus one for each lab test. OneRnd is the value that has the number of decimals needed to round to one more decimal than the maximum number of decimals for each lab. TwoFMT is the value that has the maximum number of decimals plus one for each lab test. TwoRnd is the value that has the number of decimals needed to round to two more decimal than the maximum number of decimals for each lab.

Calculating the Width and Number of Decimal Places the variable that is formatting is calculated LAB DECIMAL ONERND TWORND ONEFMT TWOFMT HCT PLT RDW 5 1E-6 1E WBC

The everyday job… PROC UNIVARIATE DATA=LABS NOPRINT; VAR RESULT; BY lab; OUTPUT OUT=STAT MEAN=MEAN STD=STD; RUN; DATA FORMATED; MERGE STAT DECIMAL; BY LAB; RMEAN=ROUND(MEAN,ONERND); FMEAN=PUTN(RMEAN,ONEFMT); FSTD=PUTN(ROUND(STD,TWORND), TWOFMT); RUN;

The end! LAB MEAN STD DECIMAL RMEAN FMEAN FSTD HCT PLT RDW WBC Rmean: the r ounded mean. SAS is choosing the format for me. All the Labs have the same format. Fmean: the formatted, rounded mean. I chose the format and the rounding. FSTD: the formatted, rounded standard deviation

Final Thoughts This presentation focuses in using the PUTN function but the method that should be used will depend on the kind of job that will be done. Factors that should be considered are: Do you need do have different formats for different lab tests How many different Laboratory tests are going to be reported. How many statistics are required. Do you need to round. If yes, I would round first and then format.

Final Thoughts If you calculate the width and maximum number of decimal places, you will do a quick review of the data. get a handy tool to give the number of decimals. most of the time, just use 32 as the width. In this case, more is more.

References SAS Technical Report P-222. Changes and Enhancements to Base SAS Software. Release 6.07

Thank YOU for being here! Also Thanks to: Jim Nezamis for teaching me the PUTN function. LaTonya Murphy, Lan Tran and Terry Strader for reviewing my presentation. Bonnie Duncan and Kim Sturgen for their encouragement.

Contact Information This was a Power Pointer Mix Presentation A.Cecilia Mauldin 3900 Paramount Parkway Morrisville, NC Voice: (919)