How risky is it to ship frozen worms?

Hello all,

I’m starting a new lab and it’s time to teleport many strains from my old lab to my new lab. I know the safe way to do this is to thaw the frozen vials to plates, parafilm, and ship normally.

But I’d rather ship the frozen vials directly, on dry ice:

  1. It’s much less work on the sending end.
  2. I don’t have equipment or materials set up yet on the receiving end to manage cultures.
  3. I’d have to freeze down live cultures ASAP again anyway (using a colleague’s resources).

Does anybody have any experience shipping frozen tubes of worms? Tips on packing with dry ice, etc? I can afford to lose a couple strains if most survive, and retrieve stragglers later. Overnight shipping is no problem (New York to Atlanta).

Advice welcome, thank you!


I’ve known people who’ve done this, and I don’t think there’s anything tricky about it.

That said, a couple of points:

  1. I have also heard of horror stories, wherein frozen samples wound up spending an extra day in a hot warehouse in Atlanta (FedEx). Bad things can happen.
  2. Resist the temptation simply to drive the samples yourself. Dry ice in a closed car is a bad idea.

I have done this both successfully and unsuccessfully, here is my advise:

  1. Plan for an extra day - assume something will go wrong and that you will not get your worms overnight
    Use a large container, the 1 foot size is too small to hold the amount of dry ice you need
    you can purchase “shippers” from Fisher or VWR that are meant for shipping and are very well insulated.
  2. Forget about the freezer boxes - put the tubes in ziplock bags, you need all of that room for dry ice.
    Pack as much dry ice as you can in the boxes just before pickup time. If you really want to keep them in boxes because you have 300 already organized strains - add a lot more dry ice.
    The boxes take up a lot of real estate. You also want to tape the boxes shut - if the boxes move around after the dry ice melts the tubes will be all over the place(I say this from experience).
    If you can only fit 2-3 large metal scoops of ice into the box, use a larger box. This is not enough dry ice. Your box should be mostly dry ice, not mostly samples.
  3. Be sure that you put all of the correct dry ice labels on the box with the weight etc. and remove any labels on the box that are not your own.
    We have had packages returned or delayed because drivers claimed packages were improperly labelled
    If you haven’t shipped anything on dry ice before with your shipping company - check with someone who has, there are always regulations that differ between companies.
  4. If you have a lot of strains I would recommend you phone around and ask companies if they have the capability to add dry ice to your package if it is delayed - some companies will do this.
    This probably isn’t a huge consideration since you aren’t sending them across a border - but if you have the option, better safe than sorry.
  5. Ship at the beginning of the week - If your shipment gets tied up into the weekend…goodbye worms
  6. If the worms are thawed when they arrive- run over to another C. elegans lab and beg for some seeded NGM plates.
    The last set of worms I received got tied up at customs and were thawed when I received them but about 70% of the tubes had some survivors.
    Good luck!


go large and use an overnight FedEx service to Atlanta.

Get someone in Atlanta to be the ‘active’ recipient, either they pick up the package at FedEx or they are there (online / on the phone) to check where the package is.

Ask FedEx or whoever you choose about the shipment requirements…often problems are caused because boxes are not labelled properly, rarely is it because they are just delayed.

As for the dry ice, well common sense says the more you have the longer it will last (sublimation rate is ~1% per hour).

I always have this romantic idea that 1300 miles in the US is like a trip to the local store, but as Hillel says, CO2 in a car is not a good idea.

How many vials will you be shipping? If you have enough that full boxes can be used, packing them in boxes will not waste much space and avoid having to repack them into boxes (including the exposure to warmer temps while doing this) on the receiving end. Send early in the week to give yourself an extra day on the receiving end in case of any delays: don’t target delivery on a Friday or a holiday, because it could get stuck somewhere over the weekend.

We have used MVE dry shippers that hold 4-5 boxes to transport of frozen strains. They are great, if you can find one to use. They are small liquid nitrogen dewers containing a matrix that will absorb liquid nitrogen and maintain temperature for about a week. Any excess liquid nitrogen is poured out before shipping, so they are exempt from hazardous shipping requirements. No problem shipping them domestically through FedEx.

You guys are great, thank you so much for these tips. The MVE dry shipper sounds ideal. I doubt I’ll find one to borrow but definitely something to keep in mind for the future.

I don’t intend to keep things in the white freezer boxes so my plan will be to get a big shipping container and pack it like crazy with dry ice and lots of individual tubes in baggies. Right now my stumbling blocks are finding a good shipping container in time (local FedEx storefronts won’t take dry ice shipments and don’t sell cold shippers) and making sure the pickup and labeling is all above board. This link is very useful.

I’ll post here again next week to report how it went, for future reference.


** UPDATE **

The worms were successfully shipped overnight. In a month or two when I have microscopes, plates, equipment, etc, I will do some thaws and verify that they survived, but I think everything looks okay. The package arrived with near-full dry ice pellets, and the tubes looked frozen. Here is what I did:

  • I pulled approximately 300 tubes from the freezer in my old lab. This was actually the difficult part. to manage this, I kept a small styrofoam of dry ice on the bench and buried a sandwich sized ziplock baggie in there. As I pulled out tubes and checked them off my spreadsheet, I dropped them in the ziplock. After approximately 20 tubes, I sealed and rolled up the ziplock and stowed it in a gallon sized ziplock that was already waiting in the -80. I went through a huge stack of small ziplocks this way and ended up with three gallon ziplocks bags about 1/2 full each. Note that this kind of packaging is technically required by FedEx; they want two layers of waterproof packaging.
  • I filled a styrofoam cooler (internal dimensions 11.5x11.5x11.5 inches—this is quite big) 1/3 full of dry ice, put in the three gallon ziplock bundles, and filled the rest with dry ice. The ratio of dry ice : worms was about 2:1.
  • I cut a bunch of cardboard to make a custom box for the styrofoam cooler. If I recall this is required (not sure why).
  • I printed out and affixed the dry ice label, found here Note that this is required by FedEx as it falls under the “dangerous goods” category. Since nothing else was “dangerous” I didn’t need any additional certificates or labels (other than the shipping label).
  • I printed and affixed a FedEx priority overnight label and scheduled a pickup.

Some notes:

  • The amount of dry ice (by weight) and the total weight and dimensions of the package was required for the labels. The amount of dry ice in this package was ~50 lbs.
  • FedEx can’t provide cold shippers and won’t ship dry ice packages from their brick-and-mortar storefronts. If you don’t have a styrofoam box you’ll have to purchase one from Fisher or from some other shipper. Regular FedEx pickups will take dry ice packages, you don’t have to do anything special to schedule that pickup.
    -When the package arrived, the dry ice had mostly settled to the bottom and the ziplock packages were mostly on the top. I would have preferred that they stayed a bit more buried. Perhaps put the actual items in deeper than I did, or otherwise structure the contents (perhaps with dividers?) in such a way to prevent that kind of settling.

Thanks Annalise for the awesome updates!