Reviewing Results and Terminating Cultures

After running the appropriate p24 antigen assay on your culture harvests, you must review and accept the results. These results are in two places:

  • By selecting the p24 assay and the Review/Edit option

  • By selecting the culture assay and the Terminate/Unterminate option.

In LDMS, terminating a culture is the process of reviewing the p24 assay results and approving them. This typically corresponds to the actual termination of the culture.

  1. Select the appropriate culture from the Assay list on the Assay Selection tab.

  2. Select the Terminate/Unterminate option, and then click the button.

  3. Select either the All Open Cultures, All Closed Cultures, or All Cultures option, depending on which cultures you want to review, and then click the button from the LDMS toolbar.


    Closed and open cultures are the same as terminated and not-terminated cultures respectively.

  4. Select the culture(s) you want to review. You can select multiple cultures and view more than one at the same time. Once they have all been selected, click the button.


    While you can use the and buttons to terminate/unterminate multiple cultures at once, this is not recommended. When you terminate a culture, you are saying that you have reviewed and approved the results; by doing this en masse, you don't actually review the results.

  5. Review the culture results. LDMS has already determined whether or not the culture is positive or negative based on the status of each harvest tested on the p24 assay. If you want to override these results, change the Culture Result option and enter a comment. If multiple cultures were selected, you can switch between them by using the database navigation buttons from the LDMS toolar.

  6. Enter the initials of the person terminating the culture into the Terminated by and your initials into the Reviewed by fields, and then complete the Reviewed Date.

  7. If you want to create an MT-2 supernatant from one of your harvests and use it to run the MT-2 assay, select the Generate MT-2 supernatant on termination option. If you do select this option, you will be prompted for the harvest date of the harvest that you want to use when terminating the culture.

  8. Select the Terminate option to accept the specimen results, the UnTerminate option to re-open a culture, or the Save option if you do not want to open or close the culture but want to save other changes.

  9. Click the button from the LDMS toolbar.

How does LDMS determine if a culture result is positive or negative?

When you review a culture's results during the termination process, LDMS will automatically set the culture result to be pos[itive], neg[ative], or ind[eterminate] based on the status from the p24 antigen assay result. You can override this automatic determination, but you may want to know how LDMS actually figures it out.

p24 Results Final Culture Result
14 Day 21 Day
Positive Not Run Positive
Negative Positive Positive
Positive Positive Positive
Positive Negative Indeterminate
Negative Not Run Negative
Negative Negative Negative

The logic for determining if a result is positive or negative is as follows:

  • If all p24 results are <30 pg/mL until at least day 28, the result is considered negative.

  • If two consecutive p24 OD values are out of range (greater than or equal to 2.0 or 3.0, depending on the assay and reader), the result is considered positive.

  • If there are two consecutive p24 values of > 30 pg/mL, and the second value is at least four times greater than the first value or is out of range, the result is considered positive.

  • If there are three consecutive p24 values of > 30 pg/mL, where the third value is at least four times greater than the first value.