Monogram FAQ: Virology

Either PPT or EDTA tubes may be used for most Monogram HIV assays, except for GenoSure Archive^® and Trofile^® DNA which requires EDTA tubes. If ordering Trofile Select, you will use one PPT tube and one EDTA tube. In general, when using EDTA tubes, the plasma must be aliquoted into labeled plastic tubes directly after centrifugation and before freezing. The exception again is GenoSure Archive^® and Trofile^® DNA, which is NOT SPUN DOWN in a centrifuge — the sample is submitted as unspun, frozen, whole-blood. 

For best results, samples should be centrifuged immediately after drawing; however, a delay of up to 1/2 hour should not significantly affect the results, provided the samples remain at ambient temperatures (20-25°C). Do not freeze and thaw the sample while waiting to centrifuge.

For successful RT/PCR amplification in Monogram’s assays, the viral genomic RNA molecule must be intact. Viral nucleic acids begin to degrade rapidly at ambient or higher temperatures. Samples are frozen as soon as possible to ensure that the integrity of the viral RNA is not compromised. 

Samples must be handled in the proper manner to assure quality results. Please contact us at 800-777-0177 or Monogram@Labcorp.com to work out the best solution for your facility.

The temperature inside the freezer should be maintained at –20°C, +/- 2°C, and checked regularly. A thermometer with the appropriate range should be kept inside an ethylene glycol-filled container in the freezer. Freezers should be monitored daily by recording the temperature on a chart, so that you can see easily if the freezer temperature starts to drift. Centrifuges should be inspected and calibrated according to the state rules governing your lab, usually at least once a year. If your centrifuge heats up significantly during the course of the day, doesn’t close properly, or starts to get much louder, it is advisable to have it serviced as soon as possible.

If a patient has a low viral load to begin with, the natural degradation of the viral RNA that can occur if samples are improperly handled may make it difficult to amplify the sample sufficiently to get an accurate result. If the patient has a high viral load, the impact of leaving a sample out a few extra minutes before spinning or freezing may not be as noticeable, but you still run the risk that you might not amplify all of the significant quasispecies (viral variants) that have developed within the patient.

Viral load can have an effect on the ease with which a good representation of the patient’s virus population can be amplified. Amplification is one of the first steps in our assay and getting a representative amplified population is vital to good test results. Lower viral load samples (< 1000 for Trofile® copies) are less liable to amplification. Or, if we are able to amplify the viral RNA, the amplified product may not be representative of the true viral population of the patient.

A resistance test is a complex assay that requires excellent sample integrity to achieve the best results. We have designed our sample collection and handling protocols to ensure that we have the best opportunity to get accurate results for your patients. In some cases, the procedures for handling our samples may be more stringent than other common blood tests because our assay is dependent on being able to extract intact viral RNA from the frozen plasma sample that you send to us. We then go through a process to amplify this viral RNA and the better condition that the original RNA arrives, the better our likelihood of getting good results. By following our sample collection requirements, you will help to ensure this. 

Call 1-800-777-0177. Monogram will dispatch a courier to your office. If you call before 1:00 PM (your local time), the courier will arrive the same day for overnight delivery to Monogram. After 1:00 PM, the pickup will be made the following day, but the sample should be maintained in the freezer during this time.

As stated above, our assay depends on proper sample collection and handling. Part of this includes ensuring that the sample is fully frozen BEFORE putting it on dry ice with the courier. It is possible that attempting to flash freeze a partially frozen or unfrozen sample directly on dry ice could negatively impact the quality of the sample. 

Logistics Manager
Monogram Biosciences, Inc.
345 Oyster Point Boulevard
South San Francisco, CA 94080
1-800-777-0177
MGBReceiving@labcorp.com