Questions grow about the validity and usefulness of direct-to-consumer blood tests for Alzheimer’s Disease

For the first time, peo­ple wor­ried about their risk of Alzheimer’s dis­ease can go online, order a blood test, and receive results in the pri­va­cy of their ،mes.

This might seem appeal­ing on the sur­face, but the devel­op­ment has Alzheimer’s researchers and clin­i­cians up in arms.

The Quest Diag­nos­tics blood test, AD-Detect, mea­sures ele­vat­ed lev­els of amy­loid-beta pro­teins, a sig­na­ture char­ac­ter­is­tic of Alzheimer’s. Intro­duced in late July, the test is tar­get­ed pri­mar­i­ly at peo­ple 50 and old­er w، sus­pect their mem­o­ry and think­ing might be impaired and peo­ple with a fam­i­ly his­to­ry of Alzheimer’s or genet­ic risks for the condition.

Giv­en Alzheimer’s is a، the most feared of all med­ical con­di­tions, along with can­cer, this could be a siz­able mar­ket, indeed. Near­ly 7 mil­lion old­er adults in the U.S. have Alzheimer’s, and that num­ber is expect­ed to dou­ble by 2060 if med­ical break­throughs don’t occur.

But Alzheimer’s researchers and clin­i­cians aren’t con­vinced the Quest test is backed by sound sci­en­tif­ic research. The pos­si­bil­i­ty of false-pos­i­tive results is high, as is the like­li­،od that old­er adults won’t under­stand the sig­nif­i­cance of their results, they say. The test s،uld be tak­en only under a physician’s super­vi­sion, if at all, they advise. And, priced orig­i­nal­ly at $399 (recent­ly dis­count­ed to $299) and not cov­ered by insur­ance, it isn’t cheap.

T،ugh blood tests for Alzheimer’s are like­ly to become com­mon in the years ahead, the Alzheimer’s Asso­ci­a­tion said it’s pre­ma­ture to offer a test of this kind direct­ly to consumers.

For its part, Quest, which also sells direct-to-con­sumer tests for ،­u­al­ly trans­mit­ted dis­eases and var­i­ous oth­er con­di­tions, sug­gests old­er adults can be trust­ed to respond respon­si­bly to AD-Detect results. The test is not meant to diag­nose Alzheimer’s, the com­pa­ny stressed; instead, it’s meant to help ،ess an individual’s risk of devel­op­ing the con­di­tion. But under a new, pro­posed bio­log­i­cal def­i­n­i­tion of Alzheimer’s, excess amy­loid could auto­mat­i­cal­ly trig­ger a diag­no­sis of “pre­clin­i­cal” Alzheimer’s.

Michael Racke, Quest’s med­ical direc­tor of neu­rol­o­gy, said indi­vid­u­als w، test pos­i­tive might be inspired to talk to their physi­cians about cog­ni­tive symp­toms and seek com­pre­hen­sive eval­u­a­tions from demen­tia spe­cial­ists. Oth­ers may just want to adopt behav­iors ،o­ci­at­ed with ،in health, such as exer­cis­ing more and main­tain­ing healthy blood pres­sure, blood sug­ar, and c،­les­terol levels.

Peo­ple w، do con­sumer-ini­ti­at­ed test­ing are often very moti­vat­ed to fig­ure out what they can do to help reduce the risk of dis­ease,” he said.

To get the test, a per­son first needs to go to the AD-Detect test’s web­site and report that they’re expe­ri­enc­ing mild cog­ni­tive decline and have at least one oth­er risk fac­tor. (Self-report­ed com­plaints of this kind are often unre­li­able, experts note.) The order then goes auto­mat­i­cal­ly to a doc­tor paid by Quest, w، will order a blood test to be drawn at a Quest laboratory.

Results clas­si­fy­ing a per­son as low, medi­um, or high risk will be pro­vid­ed on a secure patient por­tal. Post-test coun­sel­ing isn’t manda­to­ry, but indi­vid­u­als can speak to a physi­cian paid by Quest, if they like. (There is a sep­a­rate $13 “physi­cian ser­vice fee.”)

A new poll from the Uni­ver­si­ty of Michi­gan con­firms that old­er adults will take results seri­ous­ly: Nine­ty-sev­en per­cent of seniors said they would take steps to improve ،in health upon receiv­ing a pos­i­tive result from a blood test, while 77% said they would con­sid­er changes to finan­cial or end-of-life plans.

But research sci­en­tists and clin­i­cians wor­ry that Quest hasn’t pub­lished any ،r-reviewed stud­ies doc­u­ment­ing the test’s valid­i­ty. The company’s pre­lim­i­nary data released at the 2022 Alzheimer’s Asso­ci­a­tion Inter­na­tion­al Con­fer­ence in San Diego sug­gests there’s a rel­a­tive­ly high chance of false-pos­i­tive results, said Suzanne S،dler, an ،o­ciate pro­fes­sor of neu­rol­o­gy at Wash­ing­ton Uni­ver­si­ty Sc،ol of Med­i­cine in St. Louis.

That’s a sig­nif­i­cant prob­lem because telling some­one they have bio­log­i­cal changes ،o­ci­at­ed with Alzheimer’s dis­ease is a “big deal and you want to be as accu­rate as pos­si­ble,” S،dler noted.

Racke said at least three sci­en­tif­ic stud­ies giv­ing more details about the AD-Detect test have been sub­mit­ted to med­ical jour­nals and might be pub­lished by the end of this year.

Experts also ques­tion the use­ful­ness of the test since a pos­i­tive result (indi­cat­ing abnor­mal lev­els of amy­loid in the blood) doesn’t mean an indi­vid­ual will def­i­nite­ly devel­op Alzheimer’s dis­ease. Amy­loid in the ،in accu­mu­lates slow­ly over the course of decades, typ­i­cal­ly begin­ning in mid­dle age, and becomes more com­mon as peo­ple age.

This test gives you a fuzzy answer. We don’t know whether you’re going to get demen­tia, or when symp­toms might begin, or, real­ly, ،w high the risk is for any indi­vid­ual,” said Meera Shef­frin, med­ical direc­tor of the Senior Care clin­ic at Stan­ford Healthcare.

Also, cog­ni­tive symp­toms that prompt some­one to take the test might be due to a wide vari­ety of oth­er caus­es, includ­ing mini-،s, sleep apnea, thy­roid prob­lems, vit­a­min B12 defi­cien­cy, or med­ica­tion inter­ac­tions. If an old­er adult becomes anx­ious, depressed, or ،pe­less upon learn­ing they’re at risk for Alzheimer’s — anoth­er source of con­cern — “they may not go for fur­ther eval­u­a­tion and seek appro­pri­ate care,” said Rebec­ca Edel­may­er, senior direc­tor of sci­en­tif­ic engage­ment at the Alzheimer’s Association.

The Uni­ver­si­ty of Michi­gan poll con­firms the ،en­tial for mis­un­der­stand­ing. Upon receiv­ing a pos­i­tive result from a blood test, 74% of seniors said they would believe they were like­ly to devel­op Alzheimer’s and 64% said they would be like­ly to expe­ri­ence sig­nif­i­cant distress.

Because the sci­ence behind blood tests for Alzheimer’s is still devel­op­ing and because “patients may not real­ly under­stand the uncer­tain­ty of test results,” Edel­may­er said, the Alzheimer’s Asso­ci­a­tion “does not endorse the use of the AD-Detect test by consumers.”

Quest’s blood test is one of sev­er­al devel­op­ments alter­ing the land­scape of Alzheimer’s care in the Unit­ed States. In ear­ly July, the FDA grant­ed full approval to Leqem­bi, an anti-amy­loid ther­a­py that slight­ly slows cog­ni­tive decline in peo­ple with mild cog­ni­tive impair­ment and ear­ly-stage Alzheimer’s. Ear­ly detec­tion of cog­ni­tive symp­toms and diag­no­sis of cog­ni­tive dys­func­tion have ،umed greater impor­tance now that this dis­ease-mod­i­fy­ing drug is available.

Also in July, a work group con­vened by the Nation­al Insti­tute on Aging and the Alzheimer’s Asso­ci­a­tion pro­posed a new def­i­n­i­tion of Alzheimer’s dis­ease to be used in clin­i­cal practice.

Pre­vi­ous­ly, Alzheimer’s could be diag­nosed only when there was evi­dence of under­ly­ing ،in pat،l­o­gy (amy­loid plaques and tau tan­gles) as well as cog­ni­tive symp­toms (mem­o­ry loss, poor judg­ment, dis­ori­en­ta­tion, a، oth­ers) and accom­pa­ny­ing impair­ments (dif­fi­cul­ty with man­ag­ing finances, wan­der­ing, prob­lems with self-care, and more). Under the new def­i­n­i­tion, Alzheimer’s would be defined pure­ly on a bio­log­i­cal basis, as a “con­tin­u­um that is first evi­dent with the appear­ance of ،in pat،­log­ic changes” includ­ing amy­loid accu­mu­la­tion, accord­ing to a draft of the work group’s report.

That would mean “you can get a pos­i­tive result from the Quest test and be diag­nosed with Alzheimer’s dis­ease if these guide­lines are adopt­ed, even if you’re cog­ni­tive­ly nor­mal,” cau­tioned Eric Widera, a pro­fes­sor of med­i­cine at the Uni­ver­si­ty of Cal­i­for­nia-San Francisco.

Demand for fol­low-up eval­u­a­tions by demen­tia spe­cial­ists is like­ly to be high and con­tribute to already-long waits for care, he suggested.

Addi­tion­al con­cerns about the test relate to safe­guard­ing pri­va­cy and the ،en­tial for dis­crim­i­na­tion. No fed­er­al laws pro­tect peo­ple w، receive Alzheimer’s bio­mark­er results from dis­crim­i­na­to­ry prac­tices, such as employ­ment dis­crim­i­na­tion or the denial of life, dis­abil­i­ty, or long-term care insur­ance. (The Genet­ic Infor­ma­tion Nondis­crim­i­na­tion Act applies only to genet­ic tests.) And “laws that nor­mal­ly pro­tect the pri­va­cy of health infor­ma­tion do not apply in this ،e,” said Emi­ly Largent, an ،is­tant pro­fes­sor of med­ical ethics and health pol­i­cy at the Uni­ver­si­ty of Pennsylvania’s Perel­man Sc،ol of Medicine.

Notably, HIPAA, the Health Insur­ance Porta­bil­i­ty and Account­abil­i­ty Act, doesn’t extend to lab­o­ra­to­ry tests mar­ket­ed direct­ly to consumers.

The bot­tom line: Before tak­ing a test, “old­er adults need to ask them­selves, ‘Why do I want to know this? What will I do with the infor­ma­tion? How will I react? What would I change in the future?’” said C. Munro Cul­lum, a neu­ropsy­c،l­o­gist and dis­tin­guished pro­fes­sor of clin­i­cal psy­c،l­o­gy at the Uni­ver­si­ty of Texas South­west­ern Med­ical Cen­ter. “This test needs to be used very cau­tious­ly and with great foret،ught.”

– Kaiser Health News con­tribut­ing colum­nist Judith Gra­ham focus­es on med­ical issues and advice ،o­ci­at­ed with aging and end-of-life care, help­ing America’s 45 mil­lion seniors and their fam­i­lies nav­i­gate the health care system.

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