##  Routine to transform given NDC code (v\_ndc) to HIPAA 11-digit format (ret\_ndc)

###  Define variables

- v\_ndc = value of source NDC to be normalized 
- v\_rsab = RxNorm root source abbreviation (SAB)
- ret\_ndc = string(50);    'the normalized NDC
- v\_format = string(50);  'the format of source NDC code

###  Find the format of source NDC value to be normalized

###  Format can vary from source to source
```
	IF LEN(v_ndc) - LEN(REPLACE (v_ndc, '-')) = 2  ## If NDC string contains 2 dashes
	THEN              ## find the format of the NDC string.  Format could be 6-4-2, 6-4-1, 5-4-2, etc.
		v_format =
			LEN (SUBSTR (v_ndc, 1, INSTR (v_ndc, '-') - 1))  ##  find number of digits before first dash
			+ '-'
			+ LEN (SUBSTR (v_ndc,
					   INSTR (v_ndc, '-') + 1,     ## digit number after first dash
					   INSTR (v_ndc, '-', 1, 2) - INSTR (v_ndc, '-')  -1       ## number of digits between first and second dash
					   )
					)  ## find number of digits between the dashes
			+ '-'
			+ LEN (SUBSTR (v_ndc, INSTR (v_ndc, '-', 1, 2) + 1))  ## number of digits after second dash
	END IF  ##  v_format now contains ‘X-X-X’
```
###  Format has been identified.  Convert into normalized NDC
```
    IF v_format IS NOT NULL      ##  source NDC string contains dashes
    THEN
        IF v_format = '6-4-2'   ## drop first digit of string
        THEN
            ret_ndc =
               SUBSTR (v_ndc, 2, 5)  ## last 5 digits of number before first dash
             + SUBSTR (v_ndc, 8, 4)   ## all four digits after first dash
             + SUBSTR (v_ndc, 13, 2)  ##  last 2 digits after second dash
        ELSE IF v_format = '6-4-1'              ## drop first digit of string
        THEN
            ret_ndc =
                SUBSTR (v_ndc, 2, 5)
            + SUBSTR (v_ndc, 8, 4)
            + '0'                   ## pad last digit to 2 chars
            + SUBSTR (v_ndc, 13, 1)
        ELSE IF v_format = '6-3-2'              ## drop first digit of string
        THEN
            ret_ndc =
                SUBSTR (v_ndc, 2, 5)
            + '0'                    ## pad second digit to 4 chars
            + SUBSTR (v_ndc, 8, 3)
            + SUBSTR (v_ndc, 12, 2)
        ELSE IF v_format = '6-3-1'             ## drop first digit of string
        THEN
            ret_ndc =
                SUBSTR (v_ndc, 2, 5)
            + '0'               ## pad second digit to 4 chars
            + SUBSTR (v_ndc, 8, 3)
            + '0'              ## pad third digit to 2 chars
            + SUBSTR (v_ndc, 12, 1)
        ELSE IF v_format = '5-4-2'             ## keep all digits
        THEN
            ret_ndc =
                SUBSTR (v_ndc, 1, 5)
            + SUBSTR (v_ndc, 7, 4)
            + SUBSTR (v_ndc, 12, 2)
        ELSE IF v_format = '5-4-1'             ## keep all digits
        THEN
            ret_ndc =
                SUBSTR (v_ndc, 1, 5)
            + SUBSTR (v_ndc, 7, 4)
            + '0'                 ## pad third digit to 2 chars
            + SUBSTR (v_ndc, 12, 1)
        ELSE IF v_format = '5-3-2'           ## keep all digits
        THEN
            ret_ndc =
                SUBSTR (v_ndc, 1, 5)
            + '0'              ##  pad second digit to 4 chars
            + SUBSTR (v_ndc, 7, 3)
            + SUBSTR (v_ndc, 11, 2)
        ELSE IF v_format = '4-4-2'  ## keep all digits
        THEN
            ret_ndc =
                '0'                 ## pad first digit to 5 chars
            + SUBSTR (v_ndc, 1, 4)
            + SUBSTR (v_ndc, 6, 4)
            + SUBSTR (v_ndc, 11, 2)
        END IF
```
####  If NDC passed has 11 digits without any '-' then return input NDC as Normalized NDC value

####  NDC string is already in normalized format, it does not contain any dashes
```
        ELSE IF INSTR (v_ndc, '-') = 0 AND LEN (v_ndc) = 11
        THEN
            ret_ndc = v_ndc
```
####  If NDC passed has 12 digits and first char is '0' and its from VANDF then trim first char
####  VA sometimes pads '0' to make it 12 digit NDC
```
        ELSE IF INSTR (v_ndc, '-') = 0    ## no dashes in string
               AND LEN (v_ndc) = 12
            	 AND SUBSTR (v_ndc, 1, 1) = '0'    ## first digit is 0
            	 AND v_rsab = 'VANDF'
        THEN
            ret_ndc = SUBSTR (v_ndc, 2)   ## return all digits except first char which is 0
        END IF
```
####  Replace '\*' with '0' as some of the NDCs from MTHFDA contain \* instead of 0
```
     ret_ndc = REPLACE (ret_ndc, '\*', '0')
```
####  Check to see if NDC value contains any Alphanumeric values, if yes, then its an invalid NDC code
```
     IF TRIM (TRANSLATE (ret_ndc, '1234567890', ' ')) IS NOT NULL
     THEN
        ret_ndc = ''
     END IF
     RETURN ret_ndc
```
###  For any other cases, return NULL.  String cannot be normalized