How reliable is a 3 day hair collection test as AGA diagnostic? Should I even bother?

In my  opinion, three or four day hair counts are not very reliable or standardized. Dr. Rodney Sinclair (Australia)  has Published on this and has photographic examples of a 6 day standarized collection test. If it is undertaken, examination of the hairs including shafts and bulbs are important to rule out hair breakage versus hair loss. A folliscope  or photo trichogram is more statistically valid and can track density. You should be under the care of a hair loss expert who can help diagnose and treat your are hair loss.

Thank you for question. You are asking if a 3-day hair collection test is a good indicator for androgenetic alopecia. You also indicate that you started experiencing hair loss at age 50, and have been assessed by a dermatologist for the last 3.5 years. You have been prescribed Rogaine, or minoxidil, but no oral medications yet.
I can certainly give you some guidance about this. I’m a Board Certified Cosmetic Surgeon and Fellowship-trained Oculoplastic Surgeon. I’ve been in practice in Manhattan and Long Island for over 20 years. I’ve been performing hair transplants since I started my practice, and have been prescribing finasteride to male pattern hair loss patients since 1997. I’m also the founder of TrichoStem Hair Regeneration Centers, based on a system we developed for non-surgical treatment of pattern hair loss for men and women. We have patients from around the world who come to see us for this treatment.
Generally, if you are exceeding over 100 hairs shed a day, this is consistent with telogen effluvium. Androgenetic alopecia, or pattern hair loss, is more consistent with gradual hair thinning. In women, the thinning occurs all over the head, and can also be evident in the widening of the part.
To confirm female pattern hair loss, the best test would involve a scalp biopsy. We normally take biopsies from 3 parts of the scalp to confirm pattern hair loss.
As for treatment, there are limited treatments available for female pattern hair loss. You mentioned Rogaine or minoxidil, which is the most common treatment. However, minoxidil doesn’t treat hair thinning, as it’s more of a treatment to delay hair shedding, and to prolong the hair growth phase. You do mention oral medication, and many dermatologists prescribe spironolactone, which is more for inhibiting testosterone. While some female pattern hair loss patients see benefit from it, many others don’t. Platelet-rich plasma (PRP) injections are an increasingly popular treatment, but I find that PRP alone is only effective for short-term hair growth, and the number of treatments needed is variable and unpredictable.
We have been able to manage female pattern hair loss with our TrichoStem Hair Regeneration treatment. We start with a proper diagnosis of female pattern hair loss, as mentioned with taking biopsies. Upon confirmation, we prepare the Hair Regeneration treatment using platelet-rich plasma, which is taken from your own blood, and use it as an activator of the main ingredient extracellular matrix. Each treatment is customized based on a gender, age of onset of hair loss, degree of hair loss, current age, and other medical factors including other treatments used. Over 99% of our female pattern hair loss patients have seen improved hair growth and thicker hair. We pioneered this treatment in 2011, and increased our success rate through improved formulation, as well as better diagnosis of female pattern hair loss. Our female patients can discontinue using minoxidil, either by cessation, or by weaning to prevent sudden hair shedding. A single treatment can last 3-5 years, but some patients can benefit from a booster treatment at 15-24 months after the first, which we do at no extra charge.
I suggest you have a more definitive diagnosis for female pattern hair loss, and look into treatments like Hair Regeneration once you have confirmation. There are few treatments available, but female pattern hair loss can be managed better now than ever before. I hope you found this information helpful. Thank you for your question.

These are tests. No it doesn’t 100 % rule it out but can provide info. For most individuals androgenetic alopecia can be diagnosed by dermoscopy and careful examination of hair caliber. The most studied of all the hair collections is the 5 day modified hair wash test. If it doubt a biopsy can be useful too. The later are helpful in evaluating AGA, TE/CTE and situations where individuals have both conditions.