Serology Testing

Sample Collection & Shipping Guidelines

Opti-Spot® Sample Collection

  1. Materials required 
    • Opti-Spot card (available from IDEXX BioAnalytics for no charge)
    • Lancet or needle
  2.  Sample labeling
    • Label one Opti-Spot card with a unique identification number for each sample strip.
  3. Opti-Spot cards and strips
    • The Opti-Spot cards are constructed with 5 individual strips separated by perforations. The strips are easily separated along the perforation lines for individual use.
    • On each strip, a 1.0 cm2 circle is printed on the face of the Opti-Spot membrane as a guide. It is not necessary that the blood spot be centered within the circle.
  4. Opti-Spot sample collection
    • Ante-mortem blood samples may be obtained by lancing the lateral saphenous, facial or the temporal vein. Touch the Opti-Spot membrane to blood drop as it forms on the surface of the skin.
    • If the blood sample is taken by cardiocentesis, quickly dispense one drop of whole blood onto the Opti-Spot strip.
    • The blood spot should be of sufficient size (approximately 1 cm2) to nearly fill the printed circle and be of sufficient volume to saturate the membrane. The blood spot will appear similar on both sides of the membrane.
    • Allow the blood spot to dry for a minimum of one hour.
    • Once dried, fold the protective upper tab over the blood spot and tuck under the lower tab.
  5. Sample Shipment
    • It is important that the Opti-Spot strip is protected from moisture. Once dry, place Opti-Spot samples in a water-tight plastic bag containing the provided silica gel desiccant pack, and ship samples in a standard overnight envelope.

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Frequently Asked Questions

Have you tested the sensitivity and specificity for the organisms on the Global panels?

Yes, we have validated Opti-Spot on all organisms on our mouse and rat serology panels.

Do the cards expire?

No, when stored at room temperature in a dry environment the cards are stable indefinitely.

Do you supply silica desiccant packs?

Yes, silica packs will be sent with the Opti-Spot cards.

How much blood does it take to spot the strip adequately?

One large drop (approximately 25 µl) of whole blood is sufficient for primary and secondary testing.

How long should I dry the spotted strip before shipping?

Depending on the ambient environment, the blood spot is sufficiently dry after approximately 1 hour.


Is there a risk of oxidation of the blood spot due to air exposure?


Can I test founder or quarantine animals directly, since it is not a terminal collection?

Yes, because of the small sample size requirement, Opti-Spot offers a great advantage for testing quarantine and founder animals.

If I want to ship one or two samples, are the cards perforated so they can be broken off or do I have to ship a whole card along with unused dot(s)?

The Opti-Spot cards contain 5 perforated strips. You can use one or more and reserve the rest of the card/strips for future use.

Can we use submandibular or eye bleed?

Yes, blood collected from the heart, orbital plexus, facial vein, and lateral saphenous are suitable samples for testing.

Can we pool samples from different mice using one Opti-Spot DBS card?

We have not validated pooling of samples on the Opti-Spot card.


If we have collected serum as part of a study, can we spot the card the same way we would spot whole blood?

Yes, undiluted serum spotted on the Opti-Spot cards has been validated and is a suitable sample for serology testing.

How long are the samples stable once collected?

Regardless of the storage temperature, Opti-Spot DBS samples should be stored in a sealed plastic bag with a silica desiccant pack. At room temperature and 4°C, DBS samples are stable for at least 7 days.  At -20°C Opti-Spot DBS samples are stable for at least one month. Additional stability studies are ongoing.

When we store the Spot at -20° should we include the silica pack in the bag with the cards?


What about stability of DBS at -80°?

We have not evaluated the stability of DBS at -80°C; however, at -20°C DBS samples are stable for at least one month. Additional stability studies are ongoing.

Can you test a drop of blood from an animal found dead?


Is a cardiocentesis blood sample, after CO2 euthanasia, suitable for Opti-Spot sample collection?

Yes, whole blood should be spotted onto the Opti-Spot card immediately after collection to prevent clotting of the sample.

If we use petroleum jelly on the skin of mice for saphenous bleeding, will this impact the test?

Care should be taken to avoid touching the Opti-Spot card to any material other than blood or serum.

Have you validated the DBS using sublingual bleeds on rats?

No, however, any blood sample that is not contaminated by other body fluids should be suitable for testing.

Is it acceptable to overlap drops of blood on the card?


What about scant samples? I get those occasional mice that just won’t bleed but I manage to get enough to dilute for standard serology.

One large drop (approximately 25 µl) of whole blood is recommended and provides sufficient volume to perform primary and secondary testing if needed.

Can you autoclave the cards for sterile barrier use?

The Dried blood spot membrane is not adversely affected by heat/steam sterilization; however, the glue binding the card components together will melt when exposed to high temperature. Stapling the card prior to steam sterilization will prevent separation of the card components. Studies are ongoing to determine the suitability of other sterilization processes.

Can I send the samples by regular mail?

The DBS samples are stable for at least 7 days when stored at room temperature. Generally, shipments by regular mail may take 2-5 days to arrive at our lab; thus, the sample will not be adversely impacted. However, turnaround time will be delayed due to the prolonged shipping time. The cost of shipping Opti-Spot samples is greatly reduced compared to serum; therefore, we recommend using a standard overnight envelope at ambient temperature with an overnight courier service.

How many silica packs should I use when sending in the samples?

One gram (one pack) of silica provides sufficient desiccant for 10 Opti-Spot sample cards.


If I send other samples on dry ice and I have DBS cards to send, can I include the cards with the samples on dry ice or do they have to be separate?

Care should be taken to protect Opti-Spot samples from moisture when shipping with other samples on dry or wet ice.

What is your recommendation for shipping cards in the summer when it is really hot outside?

Dried blood spot samples are stable at 37°C for 24 hours when they are protected from humidity.


What is the turnaround time for DBS testing?

Once the sample is received at our lab, turnaround time is 24-36 hours for primary testing just as with serum.

Can I still send in serum or are you moving exclusively to DBS?

We will continue to test serum as well as DBS.

What about additional tests? How long does IDEXX BioAnalytics keep samples in case additional testing is needed?

Excess serology sample is cryopreserved for a minimum of three months after testing is completed.


How would an equivocal test result be handled?

Like serum, dried blood spot samples are suitable for testing by MFI, IFA, and western blot. A sample that gives an equivocal MFI result will be evaluated by IFA and/or western blot.

Can whole blood with an anticoagulant (i.e. ETDA, lithium heparin) be used to “spot” the card?

EDTA-treated whole blood is good. We haven’t tested heparin, but assume it will test the same.

Can an IFA confirmation test be run on positive samples? Or is it only MFI?

We can do all of the necessary testing on Opti-Spot DBS (i.e., MFI, IFA, and WB).


Is there a way to determine whether the samples have been exposed to high humidity or temperature in shipment so they may not give reliable results?

Yes, all samples are evaluated for antibody level. Degraded samples will have low antibody level resulting in a failed test.

In the collaborative study of 1000 samples, were there any disagreements between Opti-Spot DBS and serum?

In the collaborative studies, all samples were tested using the Global Serology Panel and there was 100% diagnostic correlation of results for paired serum and Opti-Spot DBS samples.

Opti-Spot® White Paper

Download our Dried Blood Spot Specimens for Serological Testing of Rodents white paper for more information about our Opti-Spot technology.