At-Home Rapid Strep Testing

Rapid strep test kits can be purchased by anybody to be done at home which may save parents/patients a lot of money in doctor visits for those prone to strep infections. Indeed, should a rapid strep test be positive, than you know that a doctor's visit is definitely worthwhile. (A doctor visit may still be worthwhile since a sore throat may be due to something else like cancer, aphthous ulcer, sinus infection, reflux, etc).

Such home kits (which in fact are the same kits used in medical offices) can be purchased online through Amazon. The price is surprisingly affordable at around the cost of a single copay $30 to do 25 tests.

However, with the purchase of such DIY kits, there are some pitfalls patients should be aware of if they decide to proceed.

1) Perform the internal controls that come with the kit!!! The kit may be a dud and needs to be tested against itself to ensure accurate results whether negative or positive. If the controls do not work, throw the whole test kit out and buy another.
2) You must follow the directions precisely, otherwise the test results will be unreliable. In other words, if the directions call for 4 drops, than it MUST be 4 drops (not 3 drops or 5). If directions state to wait 4 minutes... you must wait exactly 4 minutes. This literally is like precision baking.
3) The test strips need to be kept in protected, sealed bag and used immediately after taking one out, otherwise the test results will be unreliable.
4) When swabbing the throat, you MUST get the cotton tip on the tonsil and/or back wall of the mouth which than must be rubbed around a couple times. Getting the tongue or cheek will increase the risk of a false negative. As such, it may be worthwhile to invest in some tongue blades to help push the tongue down in order to perform this test properly.

Should patients elect to start performing home strep tests, please be aware that physicians will be obligated to not only REPEAT the testing but also examine the patient to ensure antibiotics are appropriate. An actual throat culture may be performed as well which is the gold standard test.

1) Repeat testing is required because the patient may not have followed the instructions precisely. For example, the test strips must be read at 5 minutes (variable depending on the kit). If test results are read past 5 minutes, it may incorrectly show a positive result.
2) Some patients unfortunately fabricate test results just so they can get an antibiotic without an office visit.
3) Some patients unfortunately also fabricate test results in order to skip work or school for personal reasons not related to an actual medical condition.
4) There are situations that even though the strep test is positive, no treatment may be recommended. The patient may be a strep carrier for which treatment of any kind is not recommended.

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We Now Offer Rapid Saliva Test to Look for Laryngopharyngeal Reflux

When you compare a spit test to the current way of how throat level reflux (LPR) is determined via barium swallow, upper endoscopy (EGD), and 24 hour ph/impedance testing, it sounds quite attractive.

And we are one of the very few offices in the United States that offer this spit test. Even major laboratory companies like Labcorp and Quest do not offer this test yet.

How does such a test work?

It basically looks for a stomach protein called pepsin.

Given reflux is when stomach contents moves up towards the mouth and pepsin is a protein ONLY produced in the stomach... pepsin should NOT be found in the throat/mouth.

As such, the test can state yes or no whether LPR is present or not.

The steps to the test are as follows:

   

How good is the test?

Depending on the study, sensitivity ranges in the 80-100% (can actually detect reflux if truly present) and specificity is around 85% (truly no reflux if test is negative).

One test company is RDbiomed (in Europe) using their Peptest kit.

This test is currently not FDA approved yet and as such, is a test that is NOT covered by insurance at this time. Due to a special arrangement our office has with RDBiomed, the Peptest kit can be obtained in our office at a discounted price of $125 (compared to normal price of $175). Price includes the kit, test supplies, and courier shipping service.

Please note that this testing is ONLY offered to current patients of ours.

However, if you are not a current patient of ours, you can order this test yourself online as an individual without a visit to our office. It is recommended you take the standard 3 sample peptest. Click here for more information.

References:
Sensitive pepsin immunoassay for detection of laryngopharyngeal reflux. Laryngoscope. 2005 Aug;115(8):1473-8.

Rapid salivary pepsin test: Blinded assessment of test performance in gastroesophageal reflux disease. Laryngoscope. 2012 Jun;122(6):1312-6. doi: 10.1002/lary.23252. Epub 2012 Mar 23.

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Why Are Some Patients Sensitive to Narcotics and Others are Not?

Blame cytochrome P450 2D6, also known as CYP2D6.

Found in the liver, it is responsible for metabolizing drugs including many narcotics.

It also determines how "sensitive" a patient is to these drugs.

For example, codeine is not bioactive until it is metabolized by CYP2D6 into morphine, the bioactive form that helps with pain.

As such, how "sensitive" a patient is to codeine is determined by how active their CYP2D6 is. The more active, the more quickly codeine is converted into morphine. The less active it is, the less morphine is created and the less pain control a patient will have when taking codeine as prescribed.

Due to the wide variability in its expression in the liver among patient populations, there will be a correspondingly large variation in how sensitive patients are to such drugs depending on how active CYP2D6 is expressed in the liver.

Such variability accounts for normal, reduced, and non-existent CYP2D6 function in patients.

• Poor Metabolizers – These patients have little or no CYP2D6 function. (Codeine will provide poor pain control.)
• Intermediate Metabolizers – These patients metabolize drugs at a rate somewhere between the poor and extensive metabolizers. (Codeine will provide some pain control.)
• Extensive (Normal) Metabolizers – These patients have normal CYP2D6 function . (Codeine will provide safe and appropriate pain control.)
• Ultra-Rapid Metabolizers – These patients have multiple copies CYP2D6 and therefore greater-than-normal CYP2D6 function. (Codeine will provide dangerous levels of pain control.)

Additionally, certain genetic variations of CYP2D6 will result in normal, decreased, or no CYP2D6 function.

Additionally, certain medications can inhibit or induce CYP2D6 functionality [read more]. Most importantly to ENT surgeons, decadron which is a steroid commonly given during or after tonsillectomy surgery increases CYP2D6 function.

This CYP2D6 variability and in particular the existence of ultra-rapid metabolizers is the reason why narcotics are strongly discouraged in the pediatric population after surgery. There have been deaths associated with codeine due to respiratory depression in those patients who have a super-active CYP2D6 resulting in too-high morphine production. High morphine levels can potentially lead a patient to stop breathing which ultimately can lead to anoxic brain injury and even death.

There is ethnic variability with CYP2D6 functionality as well. Poor metabolizers are found in less than 10% of whites, asians, and blacks. However, Middle Eastern and North African populations have a relatively higher occurrence of ultra-rapid metabolizers.

References:

More codeine fatalities after tonsillectomy in North American children. Pediatrics. 2012 May;129(5):e1343-7. Epub 2012 Apr 9.

Preventing opioid-related deaths in children undergoing surgery. Pain Med. 2012 Jul;13(7):982-3; author reply 984. doi: 10.1111/j.1526-4637.2012.01419.x. Epub 2012 Jun 13.

Comparison of three CYP2D6 probe substrates and genotype in Ghanaians, Chinese and Caucasians. Pharmacogenetics. 1998 Aug;8(4):325-33.

Unique CYP2D6 activity distribution and genotype-phenotype discordance in black Americans. Clin Pharmacol Ther. 2002 Jul;72(1):76-89.

Frequent occurrence of CYP2D6 gene duplication in Saudi Arabians. Pharmacogenetics. 1997 Jun;7(3):187-91.

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