Document ID: OSHA-2018-0003-0015
Agency: osha
Document Type: Supporting & Related Material
Title: 
Posted Date: 2018-11-29T05:00Z

Interpreting Results from the BeLPT

Below are two potential protocols for the BeLPT.  The tables represent possible outcomes of a BeLPT based on either the first sample being analyzed in a single laboratory with second analysis of a split sample (if necessary) being performed in two separate laboratories; or a split sample being analyzed in two laboratories for first analysis and a split sample being analyzed in two laboratories for the second analysis (if necessary). 

Scenario 1  -  BeLPT performed on a single sample analyzed in one laboratory with second analysis (if necessary) performed in two separate laboratories
                                       
                                 Single Sample
                                       
                              First test results
                             Abnormal result (AB)
                            Borderline result (BL)
                               Normal result (N)
                                       
                                       
      Retest sample by splitting sample and sending to two separate labs
(below represents the combination of results from first test + results from second split sample test)

                                   Negative 
                   Second test results (combined with first)
                      [AB] + AB + AB = confirmed positive
                      [BL] + AB + AB = confirmed positive
                                       
                                       
                      [AB] + AB + BL = confirmed positive
                      [BL] + AB + BL = confirmed positive
                                       
                                       
                      [AB] + AB + N = confirmed positive
                      [BL] + AB + N = confirmed positive
                                       
                                       
                      [AB] + BL + BL = confirmed positive
                      [BL] + BL + BL = confirmed positive
                                       
                                       
                      [AB] + BL + N = confirmed positive
                           [BL] + BL + N = negative 
                                       
                                       
                           [AB] + N + N = negative 
                           [BL] + N + N = negative 
                                       
Legend: AB  -  Abnormal, BL  -  Borderline, N  -  Normal
[ ]  -  results from first test

Scenario 2  -  BeLPT performed on first split sample analyzed in two laboratories (with second split sample if first test results are not conclusive)
                                       
                                 Split Sample

                              First test results
                                   AB + AB*
                                   AB + BL*
                                    AB + N
                                    BL + BL
                                    BL + N
                                     N + N
                                       
                              Confirmed positive
                              Confirmed positive
                                       
      Retest sample by splitting sample and sending to two separate labs
   (below represents the combination of results from first and second test)
                                       
                                   Negative
                   Second test results (combined with first)
                                       
                    [AB + N] + AB + AB = confirmed positive
                   [BL + BL] + AB + AB = confirmed positive
                    [BL + N] + AB + AB = confirmed positive
                                       
                                       
                                       
                    [AB + N] + AB + BL = confirmed positive
                   [BL + BL] + AB + BL = confirmed positive
                    [BL + N] + AB + BL = confirmed positive
                                       
                                       
                                       
                    [AB + N] + AB + N = confirmed positive
                    [BL + BL] + AB + N = confirmed positive
                         [BL + N] + AB + N = negative 
                                       
                                       
                                       
                    [AB + N] + BL + BL = confirmed positive
                   [BL + BL] + BL + BL = confirmed positive
                    [BL + N] + BL + BL = confirmed positive
                                       
                                       
                                       
                    [AB + N] + BL + N = confirmed positive
                    [BL + BL] + BL + N = confirmed positive
                        [BL + N] + + BL + N = negative 
                                       
                                       
                                       
                         [AB + N] + N + N = negative 
                         [BL + BL] + N + N = negative 
                         [BL + N] + N + N = negative 
                                       
Legend: AB  -  Abnormal, BL  -  Borderline, N  -  Normal
[ ]  -  results from first test
*  -  confirmed positive can occur in these scenarios without retesting