The next obvious question is “how do I find out if I am zinc deficient?” Unfortunately, as is so often the case, there is no perfect test out there available to physicians or patients. There are essentially 3 traditional ways to test and using more than one is probably appropriate:
a) Plasma Zinc Levels. This is not considered a particularly accurate way to assess zinc status, because the body powerfully responds by conserving or releasing zinc stored in the bones, liver and plasma.  In other words, plasma levels can be acceptable even though the body is depleting its reserves. This test can, of course, provide some information, especially if done over time.
b) Hair Testing. Hair testing can be useful when used as a complementary exam. For example, Dr. Cutler states the following in his book Amalgam Illness: Diagnosis and Treatment:
“Hair zinc does provide useful information about body zinc levels but interpretation can be complex since elevated hair zinc can indicate low body levels, and low zinc can too. Low hair zinc does correlate well with low red blood cell and total body zinc. Substantially elevated hair zinc is usually a sign of zinc wasting and consequent LOW body zinc levels (and low blood zinc levels). That is, people with high hair zinc usually have low red blood cell zinc and low tissue levels of zinc. Rarely will high hair zinc be due to elevated body levels of zinc. Plasma and serum zinc are reduced in acute illness and are not reliable indicators of body inventory.”
(For more information, see my page on Hair Testing Summary Page.
c) Zinc Taste Test. This exam also can provide excellent information and is popular with health bloggers. However, it is far from perfect and proponents usually do not mention some of the issues. Below I give a summary of the pros and cons:
PRO: The zinc taste test is inexpensive, can be ordered online and done in the privacy of your own home.
PRO – STUDY on Pregnant Women. A study on pregnant found the zinc taste test to be 70+% accurate and the authors concluded that “on the whole, zinc taste test was well correlated with serum zinc level, and provides a fair idea of zinc deficiency..”  Pregnant women were used, because they tend to have decreased zinc status as the pregnancy matures.
CON – TASTERS versus NON. One research summary basically brought up a very critical aspect of the zinc taste test: your native ability to taste. As you may know, there are people who are “Super Tasters,” and they tend to be the picky eaters. And then you have the other extreme, the Non-Tasters, who usually will eat just about anything and everything. The problem is that this builds a certain bias into the zinc taste test. A Super Tester may test positive for zinc, but is actually okay. This is potentially the most dangerous false read, because one does not want to oversupplement with zinc – more on that below. By the same token, a Non-Taster may be zinc deficient and yet not know it simply because he does not taste the zinc solution as strongly as he should.
The authors covered this situation with the following comments:
“Although depletion of zinc leads to decreased taste acuity, it does not explain all cases of hypogeusia. Various other influences on taste perception are discussed in relation to the validity of the ZTT. Stringent exclusion criteria are therefore mandatory to increase specificity. Large variations from the original test design have been identified..” 
CONCLUSION: The zinc taste test is actually fairly accurate according to a few small studies. However, to be ready for prime time, it really needs to be used along with a screening for one’s ability to taste food. For those who wish to try it, here is one used successfully by one of our forum posters: Designs for Health Zinc Challenge Liquid.
HOW IS THE ZINC TASTE TEST DONE? The steps are simple:
a) You consume a zinc sulfate solution after not consuming anything for a specified period of time, usually an hour.
b) You keep the solution in your mouth for (usually) 10-15 seconds.
c) You spit it out and then note if you tasted nothing, got a delayed taste reaction, got a mild taste reaction or ended up with a powerful and immediate taste reactions.
The gyst of it is that tasting nothing means that you are very zinc deficient and having a powerful and immediate nasty taste is a sign that you need no supplemental zinc.
TREATMENT DOSAGE: In my opinion, one has to be careful not to take more than about an RDA of zinc per day in my opinion. I outline why I believe this in my page on The Potential Dangers of Zinc. Some men with digestive issues probably need more, but the less risky solution is to fix the digestive issues of course. Vegetarians and flexitarians can boost their zinc status by consuming zinc rich plant foods, such as pumpkin seeds, even though some of the zinc will be bound to phytates.
NOTE: There is also study out there that shows that seniors have better abilities to taste sour and salt flavors if their zinc status is good.  These kind of observations are the reason that the zinc taste test was developed in the first place.
1) Nature, Scientific Reports, 5, 2015, “Dietary calcium and zinc deficiency risks are decreasing but remain prevalent”
2) J Nutr, 1990 Nov, 120 Suppl 11:1474-9, “Assessment of zinc status”
3) Indian J Physiol Pharmacol, 1993 Oct, 37(4):318-22, “Zinc taste test in pregnant women and its correlation with serum zinc level”
4) European Journal of Clinical Nutrition, 2005, 59(Suppl 2):S31 S36, “Zinc status and taste acuity in older Europeans: the ZENITH study”
5) The Journal of Alternative and Complementary Medicine. , Jun 2012, 18(6): 541-550, “The Accuracy of the Zinc Taste Test Method”