? about heartworm testing for dogs

pickyshopperMarch 23, 2013

I just brought my dog in for her annual exam and vaccines. Every year I also give her the anti heartworm medication. Our vet doesn't give out heartworm medication until they do the bloodwork, to ensure a dog doesn't already have heartworm. What didn't occur to me until I got home, was that my dog probably shouldn't need the heartworm blood test.

Our vet gives me a box containing 6 months of anti-heartworm treatment. However, our mosquito season here is only 4 months long, so our dog gets her first treatment one month BEFORE any mosquitoes hatch, and her last medication one month AFTER they have disappeared. In view of the fact that she is treated for heartworm every year, am I correct in thinking she shouldn't need the blood test to ensure she doesn't already have it, since there are no mosquitoes who could have possibly bitten her in the interim between treatments?

I wouldn't care if the blood test for heartworm wasn't $65.00, but we live in a major city, so vet fees are extremely costly here. If I could knock a little off my almost $400.00 annual checkup/vaccine appointment, it would help. Obviously I won't jeopardize my dog's health, but I just can't see the rationale for that heartworm blood test in this situation. Any opinions?

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I've had mine tested only once I think, he is on Trifexis. I give it to him once a month on the same day forever. Its for fleas, ticks & heart worms.The trifexis is about $18. depending on the dog's size. Vets can be expensive. See if your vet can get him on that.

    Bookmark   March 23, 2013 at 3:45PM
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Izzi gets her heart worm test every year and she is on heart worm preventive year round. It is cheaper to have them on heart worm preventive than to have to try and treat them for it.


    Bookmark   March 23, 2013 at 3:52PM
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FlamingO in AR

Our vet requires the test every year also, because nothing is guaranteed to be 100% effective and it's not good for the animal to be taking the medication if it should happen to be positive. Just because you give the medicine doesn't mean it stays in the animal- your dog could go outside and vomit up the pill and you would never know, and thus she could become infected. So the testing is done to be on the safe side. Certain companies do guarantee their preventatives should the dog test positive, but I believe you have to prove that you bought 12 doses thru the year.

We give the pills all year long, even though there is a small break during the winter where we don't see any mosquitoes, but just because I don't see them it doesn't mean there aren't any out there. It's just not a chance that I'm willing to take. I've seen mosquitoes thru December and in March before, after a slight warm up of weather.

    Bookmark   March 23, 2013 at 4:08PM
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Vets in northern Ontario only give a half year supply of heartworm medication, because mosquitoes live and die up here within 4 months. So technically, they are covering the dogs for an extra month before and an extra month after mosquito season. I'm just wondering why the expensive pre-medication blood test would be necessary, if one's dog can't possibly be exposed to mosqitoes except for the time period when they're being protected by the medication.

    Bookmark   March 23, 2013 at 4:14PM
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I don't give heartworm meds in the winter months so my dogs are tested every spring.

    Bookmark   March 23, 2013 at 4:43PM
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FlamingO, your explanation makes good sense for those who live in more temperate climates or give their dog heartworm treatment orally. However, where I live, the temperature fluctuates from just above to way below freezing in the months the dog isn't being treated, so we absolutely know there is no chance for mosquito exposure. We use Revolution for heartworm prevention, which is applied directly to the dog's skin, rather than an oral treatment that might be not digested. I suppose there is the small chance that the product doesn't actually protect the dog during the months it's being applied, but then that's even more upsetting.

    Bookmark   March 23, 2013 at 5:50PM
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IMO the blood testing is a nice stream of income for vets -- in our area. We give our Westie heartworm meds and tick preventative year 'round. Either they work or they don't. If they don't, why are we spending money to give them to our dog?

We had a big discussion about this a year or more ago on KT. You might find it using 'Search'. The only stats available about any of these diseases come from vets' reports; no one knows about the countless animals who are never seen by a vet. (Same with humans and MD's! LOL)

    Bookmark   March 23, 2013 at 6:09PM
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FlamingO in AR

I'm willing to spend the $20.50 just to be sure. Some strains of heartworm are resistant to the medications, they're finding, and are thinking that year-round application is probably better. And really, what drug is 100% effective, all the time? There are probably other things that could reduce the efficacy of the topical drug, too, like if the dog had a fever at the time it was applied, or had some antibody thing going on inside it.

We had one dog test positive while she was on year-round oral HWP, but it turned out to be a false positive, after 3 more tests. That was scary, because we didn't think she'd ever missed a dose. After sending off a more complex blood test to a lab, it turned out to be negative.

I worked for a vet in FL where HW's were very prevalent and it really drummed into me the importance of prevention. Necropsies on dogs whose hearts and arteries were clogged with long white heartworms were very eye opening.

I did a quick search and found this-

Here is a link that might be useful: Resistance to medication.

    Bookmark   March 23, 2013 at 7:27PM
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Around here the heart-worm test is paired with Lyme.
I did turn it down for Jetty who is on the Lyme vaccine. Sage has tested positive for Lyme so she had the test and is still positive (duh). She also had the Lyme vaccine and I questioned it and they said it would make the Lyme less severe..If she limps, I am supposed to get antibiotics for her.
I just spent well over $300 on shots and tests and turned down the senior blood work for Sage this time and turned down fecals on both.
You feel like a bad dog mom when you turn down tests, but you need to be realistic too.
Jetty will have a heart-worm test next year. Both are on the heart-worm meds year round.
A friend did her own shots and got in trouble from the humane society because in PA a vet needs to give rabies shots...
The horses are another story...they require a Coggins test. They could get bitten by an infected mosquito the next day - but if you want to show or do trail rides they want that overpriced piece of paper that is only good for the day the blood was drawn.
I've been delaying that...

    Bookmark   March 23, 2013 at 7:41PM
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Please keep in mind that if your dog does get HW, the treatment is very rough on them, and can even lead to death. Pay for the test, the treatment is even more.
Here in Chicago, we give the preventative year round. I have seen the mosquitos in December and just saw one on Monday. The temp was only 37.

    Bookmark   March 23, 2013 at 9:19PM
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I'm all for preventing heartworm. I just don't understand why any dog needs an annual TEST for it if he's been given the meds -- purchased at the vet -- year 'round for 13 years.

I don't even think there's much risk of heartworm in the Chicagoland area year 'round -- but who can know that, so we give the meds.

The blood testing seems a waste of money -- unless the meds are so unreliable, in which case...why prescribe them? I'll bet if your dog developed heartworm the manufacturer of the medication would not be held liable to pay for treatment; the meds in question would be long gone (couldn't be tested) and the manufacturer could claim that the owner failed to administer the meds (no proof).

I realize some owners only claim to have given the meds as prescribed when they have not, but IMO you should have the right to refuse the test when YOU know you have given the meds monthly as prescribed.

(This reminds me of a 'make work' requirement in our town. We have to have a licensed plumber test the backflow valve on our underground sprinkling system annually. I wonder when and where anyone's potable water was contaminated via this valve and why only a licensed plumber must check it.)

    Bookmark   March 24, 2013 at 11:32AM
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FlamingO in AR

I wonder if the vet's malpractice insurance company requires the testing to be done as a CYA measure?

Interceptor brand does guarantee their medication and will pay for the treatment if a dog that was on it for the full year does happen to contract heartworms. I'm not sure about other companies.

    Bookmark   March 24, 2013 at 11:49AM
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Our dog (we live in Toronto, Ontario) is on heartworm meds year round - used to be just for the normal 6 months. But stats showed that dogs were coming down with stomach ailments due to worms etc. during our so-called warmer winters - eating stuff on the ground etc. and our dog is a super hoover. He has been on year round heartworm meds for 4 years now - expensive, yes, but not as expensive as heartworm treatment or a trip to the vet and tests should he get a stomach virus in Jan. I, too asked the question re annual testing and was told that it is recommended since many people forget to give their dogs their monthly doses on time - forgetting for as long as 2 weeks to a month - so better safe than sorry. We are going April 8 for the 9th physical and he will be getting all of this year's required shots plus the heartworm test and the vaccine for lepto. He tolerates the lepto shot and since there was a major outbreak with many canine deaths in Toronto a few years ago, better to err on the side of caution plus we have a lot of raccoons and now coyotes. He gets his Kennel Cough shot in Jan. just because it worked out that way re boarding. More expensive to do it at a different time of year, but one less shot during a full year (rabies does not have to be given every year - but this year he is up). We will not need the senior blood panel because we had yet another dental this year - panel costs about $700 - so we have it done just before a cleaning. We will be having a fecal specimen analyzed - but I sure wish they made the containers the size they used to. Our dog weighs 24 lbs. and it is a stretch. I don't know what people with Great Danes do. We are also going to have to try a different heartworm which I do not look forward to. The first year we had our double-coated Eskie he was on topical - a nightmare for me to find a pink spot on his and have my husband ready with the topical. The next year the manufacturers recommended chewables for such dogs to ensure that all of the meds were absorbed. But Novartis is having problems with Sentinel again this year - last year it came back just in time - but not this year. So we will have to take one of 2 different types of topicals. I will go with whatever one the vet recommends and hope that it works out okay for him. Bottom line is it is very expensive to have a dog or cat these days!

    Bookmark   March 24, 2013 at 2:17PM
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If you think your vet is too expensive, it probably is. I really liked the vet I went to the first few years I was here but her prices kept going up, up, up. I discussed it with her but no results. I changed vets and save lots of money. My current vet is highly respected and doesn't order tests just to pad her income. If you take a pet in for shots, you are not charged an office visit, just the charge for the shots. She asked that I bring a cat back in 2 weeks so she could recheck her and said there would be no charge for that visit. She is a popular vet here because people tell their friends.

    Bookmark   March 24, 2013 at 3:18PM
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linda, unfortunately, all the vets are very expensive in this area, so I was hoping I could eliminate the $65.00 pre heartworm blood test from my $400.00 annual checkup bill. I'm pretty darned sure that since my dog is medicated one whole month before and after any mosquitoes are seen in this area, there's not much chance she's ever bitten when she isn't already on the medication. However FlamingO's link shows that in some cases, heartworm can be resistant to the medication and dogs are still developing it. I guess I'll have to continue with the $65.00 pre blood test, just for insurance.

    Bookmark   March 24, 2013 at 4:43PM
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Lurker checking in. The reason the blood test is mandatory annually is that if the animal has heartworm, and you give the HW meds, it can be very harmful to the animal. According to the Novartis interceptor website, "ALWAYS have your dog tested for heartworms before starting a preventive regimen. Giving a preventive to a dog that is already heartworm-positive can cause further complications." The vet I worked for yrs ago said it could poison them if they were positive. fda.gov hw website says "Also, giving a heartworm preventive to a dog that has an adult heartworm infection may be harmful or deadly. If microfilariae are in the dogâÂÂs bloodstream, the preventive may cause the microfilariae to suddenly die, triggering a shock-like reaction and possibly death in some dogs. "

This particular test isn't solely for income, it's to protect your pets from a terrible death. And even if you give hw meds all yr, there's a small chance that the pet could still be bitten & get hw despite the meds. The treatment for a hw positive dog is awful for them to endure, and much more expensive than if you test & give preventative hw meds. The vet I worked for used to cross his fingers & watch the dog closely after each hw treatment, they can die easily from the treatments. It was scary & unnecessary for the dog to endure.

PSA over, carry on everyone!

Here is a link that might be useful: fda hw page

    Bookmark   March 24, 2013 at 5:42PM
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I believe some Vets, mine included, do an annual test because the prevention medication isn't 100% effective. In the past they also thought giving the prevention med was dangerous if the dog did have heartworm. I believe that is no longer true.

    Bookmark   March 24, 2013 at 7:29PM
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Since my dd wants to get a dog this summer, I decided to google heartworm, etc. and found this interesting article, which I'm inclined to believe. (I read all the comments as well.) I am appalled at the amount of money people are paying their vets. Come to think of it, the article reads like something Cynic may have written. :)

Huh. When I tried to paste the ulr in the box, it would not be accepted.


    Bookmark   March 24, 2013 at 7:59PM
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Country Sunflower

Both of my girls are on Trifexis... and I administer it to them every 1st day of the month.. every month... My neice who lives in Wichita. only did her dogs heartworm meds for 8 months out of the year.. and her dog got heartworms... It seems that the larvae can survive for quite a while even on meds... And short story.. it cost her a small fortune to get rid of the heartworms..

Heartworm test at our vet is $12.50 per pooch..


    Bookmark   March 24, 2013 at 9:56PM
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Ok jumping in here..of course I live in the south were skeeters are bad bad bad.
Bear(my last Saint) tested positive for heart-worms...We changed up his meds and at his next visit..He tested negative. After his death and we got Tank..we made sure he got his pills on the 16th of every single month. later he tested positive for heart worms..but since I was buying pills for two different dogs they wouldn't cover his cost. We gave him antibiotics and then also changed what he was on..Later he tested negative.. My vet told me that some dogs develop a resistance to the meds.. I would bite the bullet and get them tested...

    Bookmark   March 24, 2013 at 10:07PM
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We give our dog Interceptor on the 27th of every single month. He gets tested once a year for heartworm. He also gets Vectra D for fleas/ticks.

We have a weekend home in Pennsylvania in the woods (mosquitoes and ticks always a problem).

We know our vet is not cheap, but he and his associates are part of an accredited animal hospital, and they're a 2 minute drive (10 minute walk) from our home on Long Island.

Paying for the testing is paying for peace of mind.

    Bookmark   March 25, 2013 at 10:33AM
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Vets can be like: physicians who do unnecessary tests/procedures or dentists who direct patients toward more expensive or unneeded procedures or the HVAC contractor who scares you into thinking your house is going to burn down unless you buy something new or .... or.....

Vets can also be honest and caring, just like many who work in the types of professionals mentioned.

There's no sense in paying someone for advice you don't trust or follow. I trust my vet, who told me that taking the meds all year and having an annual test is the right approach. Each of you needs to find someone you like and then do what you're told if you want to provide your pet with the best possible care.

    Bookmark   March 25, 2013 at 12:46PM
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interesting thread, of a subject that has been very much
on my mind.

I live in the country, people drop off dogs & leave
them to starve.
at most I've had 8 dogs, currently am in the process of
going from 2 to 3 dogs.

my oldest girl I inherited from my best friend when
she died. Lizzie is 11 years old. never had
heartworms. on flea meds that provide heartworm
meds as per vet.

Teter was abandoned by his owner when he got
fired at the horse farm next door. he was young..
and kinda wild. he has settled down & is about
2 1/2 years old.
when I first got him, I took him for shots & tests.
tested positive for heartworms.
this is the course of action my vet deciced upon for
100 mg of doxcycline (sp) once a day for 30 days.
then two months of no meds. for two years.
this in conjunction with the flea/heartworm meds
monthly is supposed to kill the heartworms & be
a gentler cure than the tradtional treatment.

the vet explained to me that the traditional treatement
is expensive, but more of an issue to me was that
I'd have to keep Tee 'still & quiet' for 90 days.
if y'all have puppies...you know how active they are.
for Tee...it would be life changing, and IMO not
worth taking away his joy of chasing rabbits birds
possums & lizards.

I keep both dogs on the flea meds year round as
advised by vet. while I agree that some vets charge
more than they should, my vet isn't like that.
after a life time of dogs & vets...you can tell the
keepers from the one time only vets.

now there is a dog that just started living under my house.
she appears to be part chow..but small probably
30 lbs. so scared I can't get close to her.. but I've
been talking to her, and of course feeding her.

looks like she/he (who knows??) will be one of the
crew now. just to get her over being so afraid.
this dog has been in the neighborhood for several
months...I thought she belonged to someone.
but so far no one has claimed her.

when I work in the yard...she comes out and plays
with Tee...Lizzie scares her.

wish me luck with this new one...she/he.(0ne day I'll
get close enough to know ) needs a home.
hopefully she'll allow us to provide that.

and btw....it is soon going to be snake season.
last year...3 times Tee got bitten. my yard is clear
of debris, but woods are around my house.
any super duper snake away tips?
his last bite took us to emergency vet at 10 pm.
I've never seen a dog swell up so big.
he is ok...but I worry about this summer.
even chasing him around with a dead snake
hasn't detered him from protecting his space?

love your pets everyone...they are with us
such a short time.

    Bookmark   March 28, 2013 at 2:45PM
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