sub parse_lab_test {
    @segs = split('\r', $b);  # \r is the record terminator
    foreach $seg (@segs) {
        $segtype = substr($seg, 0, 3);
        if ($segtype eq "MSH") {
           msh_fields($seg);
        } elsif ($segtype eq "PID") {
           pid_fields($seg);
        } elsif ($segtype eq "PV1") {
           pv1_fields($seg);

		  ... etc ...

	} else {
           &segment_error;
        } 
    }
}


##</code><code>##

sub msh_fields {
    ($mshseg) =  @_;
    @vals      = split('\|', $mshseg);
    $docsource = $vals[3];
    $trandate  = $vals[6];
    $doctype2  = $vals[7];
    $rectype   = $vals[8];   
    $unique_hl7_id  = $vals[9];
    if ($rectype ne 'ORU^R01'){    # Discrete Results only
 		 next MAIN;     # Label that ends the script
    } 
}