primary care telehealth Archives

If a result in your patient portal is marked critical, or you see a number that looks dangerously high or low and you feel unwell, do not wait for a callback. Call the clinician who ordered the test right now. If you also have chest pain, trouble breathing, confusion, fainting, or severe weakness, call 911 or go to the nearest emergency department.

If you feel fine and the result is only flagged high or low, it is usually not an emergency. A message or phone call during business hours is the right speed.

The hard part is telling those two situations apart when the result lands on your phone at 9 p.m. and nobody has explained it. So here is how it works, which numbers matter, and what to do.

Why results show up before anyone has called you

The 21st Century Cures Act information-blocking rules changed the default. The prohibition began applying on April 5, 2021, and from October 6, 2022 it covered the full electronic health information in the designated record set rather than a narrower list of data elements (1). Federal guidance does not tell health systems to push every result to you the moment it posts. It does say that once a patient asks for access, the response has to be timely, and in practice you may see a result at about the same time the ordering clinician does (2).

Holding results back for clinician review is hard to defend as a blanket policy. The same federal FAQs say a routine several-day delay across a broad range of results does not qualify for the Preventing Harm exception (3). An individual clinician can make a specific determination that releasing one result would put someone’s life or physical safety at risk, and a patient can ask for a delay on their own results (3,4). Enforcement is no longer theoretical either. Provider disincentives tied to Medicare programs were finalized in July 2024, and HHS announced in September 2025 that information-blocking enforcement is a priority (5).

Patients, for what it is worth, mostly like this. In a four-center survey of 8,139 people, 95.7 percent wanted results in the portal immediately, even before a clinician reviewed them. But 16.5 percent of people with not-normal results reported being more worried afterward, against 5.0 percent of those with normal results (6). That worry is what this post is for.

What does “critical” actually mean?

A critical value is a lab result that suggests something imminently life-threatening. Federal lab regulations under CLIA require the laboratory to immediately alert the person who requested the test when a result indicates an imminently life-threatening condition, or a panic or alert value (7). The Joint Commission describes a critical value as one requiring immediate communication of results (8).

Notice who gets the call. The lab calls the ordering clinician, not you. One hospital laboratory described its rule as a technologist phoning the ordering practitioner within 30 minutes, with escalation if that person cannot be reached (8). Each lab builds its own list and its own cutoffs, and accreditors including the College of American Pathologists and the Joint Commission expect an alert system to exist (8). That obligation runs separately from whatever your portal shows you.

What the portal shows is a different matter. ONC’s safety guide for test result reporting recommends that critical values be flagged differently from ordinary abnormal values in the record clinicians use (9). Whether your portal does the same depends on the system. Do not count on a special color or the word “critical” appearing.

Flagged does not mean dangerous

Reference ranges are built from the central 95 percent of results in a healthy group. By definition, that labels 5 percent of healthy people as abnormal on any single test (10). Order a panel of 20 tests and about 64 percent of healthy people will have at least one result flagged (10). MedlinePlus puts it plainly: it is common for healthy people to sometimes have results outside the reference range (11).

So the red H or L next to your result is a prompt to look, not a verdict. A potassium of 5.6 mmol/L, for example, sits in the mild band (5.5 to 5.9) of the UK Kidney Association’s hyperkalaemia grading, and the same guideline says most mild or moderate cases found in the community can be managed without admission unless the person is acutely unwell (12). A sodium of 132 falls in the mild hyponatremia band, 130 to 135 (13). Both are real findings that deserve a conversation. Neither is a 911 call in a person who feels well.

One more trap. A hemolyzed blood sample can make potassium read falsely high, and that guideline recommends paired samples when this pseudo-hyperkalaemia is suspected (12). A surprising potassium in someone with no symptoms and normal kidney function is a reasonable one to repeat before anyone panics.

Which numbers can be truly urgent?

Labs call a wide range of analytes. Electrolytes, especially potassium, hemoglobin, high blood glucose and positive blood cultures were all on one laboratory survey’s list of commonly called values (8). I am not going to hand you a universal cutoff for each, because your lab sets its own. But the published guidelines give a sense of where the danger starts.

Potassium first. The UK Kidney Association grades severe hyperkalaemia as 6.5 mmol/L or higher and recommends urgent hospital assessment for anyone with that level found in the community (12). Sodium next. The European hyponatraemia guideline calls a serum sodium below 125 mmol/L profound, and notes that symptoms become more common below that level. Nausea, confusion and headache count as moderately severe symptoms. Vomiting, seizures, deep sleepiness and coma count as severe (13).

Glucose runs both directions. The American Diabetes Association defines level 2 hypoglycemia as below 54 mg/dL, and level 3 as an event with altered mental or physical status that needs another person’s help, whatever the glucose number says (14). On the high side, the ADA says to seek immediate care if you cannot keep fluids down, have ongoing vomiting, or have altered mental status (14). Those symptoms matter more than the number.

Hemoglobin is context-heavy. In the 2023 AABB guideline, the transfusion threshold for stable hospitalized adults is below 7 g/dL (15). That is a transfusion trigger and not a lab’s critical cutoff, but it tells you what kind of low is alarming. A slowly developed anemia and a bleed produce very different pictures at the same number.

Troponin deserves its own warning because patients see it more often now. Each assay has its own 99th percentile cutoff, reported in ng/L, and a value above it means myocardial injury. It is sensitive for a heart attack but not specific for one (16). If you see an elevated troponin in your portal and you have chest pressure, shortness of breath, or pain spreading to the arm or jaw, call 911 immediately (17). My view is that an unneeded trip to the emergency department is a much better outcome than a delayed one.

Some results always get a phone call from me: a critical blood sugar, a critical potassium, a critical kidney function result, or another electrolyte in the critical range. It is easier to reach someone during office hours, but I treat a critical result as urgent no matter what time it comes in. A critical number can occasionally be a mistake, too. A lab error, or a hemolyzed sample, where red cells broke open after the draw, can show an artificially high potassium. That is one reason earlier results help so much. For new patients I try to get their previous lab work, so I have something to compare against when I order new tests. It isn’t always possible.

What to do, in order

Start with how you feel, not with the number. Any chest pain, trouble breathing, fainting, new confusion, seizure, or severe weakness means 911, whatever the result says.

If you feel okay, check the reference range printed on your own report and read the lab’s comment, if there is one. Then call the office that ordered the test. Portal messages are the wrong tool for anything you think might be urgent. Pick up the phone.

After hours, call anyway and ask for the on-call clinician. If no one can be reached and the value is in the range described above (a potassium of 6.5 or higher, or a sodium under 125), go to an emergency department. A drawn glucose is old news by the time you read it, so for glucose, how you feel right now decides. Bring the result, your medication list, and the name of the ordering clinician.

Do not wait for the next business day with a severe value because you assume someone has already been called. The lab alert exists, but a phone number can be wrong and a message can sit in a queue.

When a virtual clinician ordered the test

Telehealth adds a wrinkle. The lab you walked into is probably near your home, while the clinician who ordered the test may be in another city or time zone. The ONC guide says the ordering clinician is responsible for follow-up of outpatient results unless that responsibility is delegated to someone else, and the delegation should be documented and accepted (9). That is the right principle. You want to know that someone actually holds it.

Ask which phone number the lab has on file for the ordering clinician, and whether that number is monitored when the clinician is not in a visit. Make sure the lab has your current cell number. And know where you are during a video visit, because a clinician who needs to send help has to know your physical address.

When a lab I ordered comes back critical, I try to reach the patient directly, especially after hours, because they need to know. They may know before I do, since the lab sometimes releases the result to them first. I also try to loop in their primary care physician if they have one. And a local emergency contact in the chart helps in the situations where the patient can’t be reached.

Ask before the blood draw

The single best question is “Who calls me if a result is critical, and from what number?” Ask it when the test is ordered, not when the portal pings you.

Follow with three more. Will I see results before you have read them? Who covers if you are unavailable? And if I would rather talk first, can the release wait? Federal guidance treats a patient’s own request to delay as likely not an interference, as long as the delay lasts no longer than necessary to meet that request (4). Some people genuinely prefer to hear a frightening result from a person first. That is a legitimate choice.

For patients, and for clinicians

If you are the patient

Know your own phone number on file, keep your ringer on after a blood draw, and decide ahead of time who you will call. Write the question “who calls me if it is critical” in your notes app before the next lab visit. Treat symptoms as the deciding factor.

If you are the clinician

Tell patients when you order that results may post before you have seen them, since the evidence shows abnormal results raise worry more often (6). Keep your critical-value contact information current with every lab you use, and make sure patients know who is covering when you are not. The SAFER guide asks organizations to have policies for timely patient notification of both normal and abnormal results, with the timeliness monitored (9).

When I order labs, I tell patients which tests are on the list. For my patients that usually means a fasting lipid profile, a comprehensive metabolic panel, a TSH, a hemoglobin A1c, and a high-sensitivity C-reactive protein, plus two special lipid tests: lipoprotein(a), which the 2026 ACC/AHA dyslipidemia guideline recommends measuring at least once in every adult (18), and apolipoprotein B.

The Bottom Line

A result marked critical, or a very high or low number paired with symptoms, means call the ordering clinician now, and call 911 for chest pain, trouble breathing, confusion, or fainting. A result that is merely flagged high or low is common even in healthy people and can usually wait for a conversation.

Cures Act rules mean you will often see results first, so ask before the blood draw who calls you if something is critical, from what number, and what happens when they cannot reach you. For telehealth patients, that answer matters even more.

Sources

Department of Health and Human Services. Information Blocking and the ONC Health IT Certification Program: Extension of Compliance Dates and Timeframes in Response to the COVID-19 Public Health Emergency. Federal Register, November 4, 2020. https://www.govinfo.gov/content/pkg/FR-2020-11-04/html/2020-24376.htm
ASTP/ONC. FAQ: Are actors (for example, health care providers) expected to release test results to patients through a patient portal or API as soon as the ordering clinician can see them? https://healthit.gov/faq/are-actors-example-health-care-providers-expected-release-test-results-patients-through-patient/
ASTP/ONC. FAQ: Would the Preventing Harm Exception cover a blanket several-day delay in the release of laboratory or other test results? https://healthit.gov/faq/would-preventing-harm-exception-cover-blanket-several-day-delay-release-laboratory-or-other/
ASTP/ONC. FAQ: Can an actor grant a patient’s request to delay the release of the patient’s test results? https://healthit.gov/faq/can-actor-grant-patients-request-delay-release-patients-test-results-eg-laboratory-or-image/
Liebler AJ, Sullivan S, Boyer MD, Doe K. Information Blocking Enforcement Enters a New Phase: What Digital Health Stakeholders Should Expect in 2026. Alston & Bird Health Care Advisory. February 23, 2026. https://www.alston.com/en/insights/publications/2026/02/information-blocking-enforcement-2026
Steitz BD, Turer RW, Lin CT, et al. Perspectives of patients about immediate access to test results through an online patient portal. JAMA Netw Open. 2023;6(3):e233572. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2802672
42 CFR 493.1291. Test report (CLIA), paragraph (g). https://www.law.cornell.edu/cfr/text/42/493.1291
Association for Diagnostics & Laboratory Medicine. Critical result notification preferences. Clinical Laboratory News. September-October 2024. https://myadlm.org/cln/Articles/2024/SeptemberOctober/Critical-result-notification-preferences
ONC. SAFER Guides: Test Results Reporting and Follow-Up. August 2024 self-assessment. https://www.healthit.gov/sites/default/files/topiclanding/2025-01/8.%20Test%20Results%20Reporting%20Final.pdf
Doles N, Ye Mon M, Shaikh A, et al. Interpreting normal values and reference ranges for laboratory tests. J Am Board Fam Med. 2025;38(1):174-179. https://pmc.ncbi.nlm.nih.gov/articles/PMC12096374/
MedlinePlus. How to Understand Your Lab Results. Updated September 4, 2025. https://medlineplus.gov/lab-tests/how-to-understand-your-lab-results/
UK Kidney Association. Clinical Practice Guideline: Management of Hyperkalaemia in Adults. Updated July 2026. https://www.ukkidney.org/sites/default/files/documents/FINAL%20VERSION%20-%20UKKA%20CLINICAL%20PRACTICE%20GUIDELINE%20-%20MANAGEMENT%20OF%20HYPERKALAEMIA%20IN%20ADULTS%20-%20UPDATED%20JULY%202026_0.pdf
Spasovski G, Vanholder R, Allolio B, et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Eur J Endocrinol. 2014;170(3):G1-G47. https://doi.org/10.1530/EJE-13-1020
American Diabetes Association Professional Practice Committee. 6. Glycemic goals, hypoglycemia, and hyperglycemic crises: Standards of Care in Diabetes-2026. Diabetes Care. 2026;49(Suppl 1):S132-S149. https://doi.org/10.2337/dc26-S006
Carson JL, Stanworth SJ, Guyatt G, et al. Red blood cell transfusion: 2023 AABB international guidelines. JAMA. 2023;330(19):1892-1902. https://doi.org/10.1001/jama.2023.12914
Sandoval Y, Apple FS, Mahler SA. High-sensitivity cardiac troponin and the 2021 guidelines for acute chest pain. American College of Cardiology. July 14, 2022. https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2022/07/14/18/12/high-sensitivity-ctn-and-2021-chest-pain
Centers for Disease Control and Prevention. About Heart Attack Symptoms, Risk, and Recovery. October 24, 2024. https://www.cdc.gov/heart-disease/about/heart-attack.html
American College of Cardiology. Lower Sooner: How the 2026 Dyslipidemia Guideline Changes Practice. July 1, 2026. https://www.acc.org/latest-in-cardiology/articles/2026/07/01/01/prioritizing-health

Telemedicine has become part of everyday care, and for good reason; it allows patients to connect with a physician from home, from work, or while traveling; and many problems can be managed safely and effectively through video visits. But not everything belongs in a virtual setting.

I follow guidelines, like the ones Teladoc, MDLive, and Amwell use, that help decide what’s safe to manage online and what has to be seen in person. Those rules aren’t arbitrary. They’re built around safety, the limits of a video encounter, and the risk of missing something serious.

What Actually Keeps a Visit Off Camera

Some diagnoses depend on a tool or a test that doesn’t exist on a video call. An ear infection needs a direct look at the eardrum through an otoscope. Ear pain alone could just as easily mean wax buildup, dental pain, or referred throat irritation, and without visualizing the drum, the real cause gets missed (swimmer’s ear is the exception, along with cases where a family can upload a high-quality otoscope photo). A suspected blood clot in the leg, deep vein thrombosis, has exactly one way to confirm or rule out: an ultrasound, which no video visit can provide. Pneumonia works the same way. A cough that persists, worsens, or comes with fever and shortness of breath needs a chest x-ray and sometimes labs. Neither of which exists on a screen. Pediatric urinary tract infections need a urine sample tested before treatment. And abnormal uterine bleeding, which can signal serious gynecologic issues, usually needs labs or imaging to sort out.

Other conditions need hands-on assessment. Looking is not enough. Post-operative pain that’s worsening rather than expected can mean infection, bleeding, or a wound problem, and a physical exam is needed to check for swelling, drainage, or fever. Post-op patients are safest going back to their surgeon. Mastitis is similar. Breast pain and redness in a breastfeeding patient could be simple mastitis or could be an abscess that needs drainage. And a virtual exam cannot reliably tell the difference. Any laceration or wound that needs stitches has to be assessed and repaired in person; so do animal bites, dog, cat, or human, because of the infection risk and sometimes rabies exposure; and wound care, tetanus updates, and rabies prophylaxis all have to happen in the room.

A third group can turn dangerous fast and needs hospital-level resources. A fever over 103°F, or any systemic illness, can point to sepsis, meningitis, pneumonia, or another serious infection needing immediate labs, imaging, or IV treatment. Suspected meningitis, headache with fever and a stiff neck, needs immediate hospital evaluation with spinal fluid testing and IV antibiotics. It cannot be managed on a screen. Croup in a child, the barking cough and stridor, can worsen quickly enough that treatments like racemic epinephrine or oxygen have to happen in person and urgently. A skin abscess on the face, or periorbital cellulitis, can spread to deeper tissue including the brain and needs urgent evaluation, often with IV antibiotics. Suspected sepsis or a bloodstream infection has to be treated urgently in a hospital, full stop. Unexplained abdominal pain could be appendicitis, gallbladder disease, a bowel obstruction, or another emergency. And usually needs imaging and labs to sort out. Chest pain gets taken most seriously of all. It can represent a heart attack, a pulmonary embolism, or another life-threatening problem, and it gets an urgent in-person evaluation every time. The same logic covers a headache described as the worst of someone’s life, which can mean bleeding in the brain or meningitis; a concussion or closed head injury, which needs a neurologic exam and sometimes imaging; and eye problems like a foreign body, a chemical burn, sudden vision loss, or trauma, all of which need immediate in-person evaluation.

A last group has nothing to do with how sick someone looks and everything to do with what has to happen in a room. Controlled substances, stimulants, opioids, benzodiazepines, carry real risk of misuse and dependence. So regulations require in-person visits for initiation and refills. Some STD treatments need an in-office procedure; genital warts are the clearest example. And anything tied to a work-related claim, FMLA paperwork, workers’ comp, a disability determination, usually needs physical documentation and an in-person exam to be valid.

What About Rashes?

Rashes are a gray zone in telemedicine. Sometimes they are straightforward, like ringworm or athlete’s foot, and can be treated virtually with antifungal creams. Other times they are difficult to interpret. Safely treating a rash through telemedicine depends heavily on two things. The quality of the photo the patient uploads and a detailed medical history.

If the picture is blurry, poorly lit, or taken at the wrong angle, it may be impossible to tell the difference between something benign and something serious. Something like shingles or cellulitis. Even with good photos, asking the right questions, when it started, whether it itches, spreads, or comes with fever, can take time to sort out.

Diagnosing rashes virtually can sometimes be challenging, which is exactly why tele-dermatology has become its own field. Companies such as Teladoc now offer access to board-certified dermatologists who specialize in skin conditions. Patients can upload high-quality images and receive expert input, which improves accuracy and treatment options.

Conditions That Can Often Be Managed Virtually

Plenty of complaints are safe to handle over video: viral upper respiratory infections, sinus infections, uncomplicated urinary tract infections, mild to moderate asthma exacerbations, vaginal yeast infections, bronchitis without red-flag symptoms, most pink eye, cold sores, sprains and strains, seasonal allergies, skin conditions like eczema, ringworm, and jock itch, uncomplicated headaches or low back pain, and early or uncomplicated dental infections.

When a “Simple” Complaint Turns Out Not to Be

Patients don’t always see the warnings that some conditions can’t be managed online, and even when they do, some push back because getting to a clinic in person is inconvenient or expensive. Sometimes what looks straightforward at first turns into something else once the clarifying questions start: a “sinus infection” complaint that turns out to be severe facial swelling, a “back pain” complaint that turns out to come with fever and urinary incontinence. In my own practice, abdominal pain is the one that converts to an in-person visit almost every time, because it needs a hands-on exam. Boils and abscesses, febrile urinary tract infections, and rashes I can’t visualize well enough on a photo make up most of the rest.

Where These Guidelines Come From

Companies such as Teladoc, MDLive, and Amwell built their red-flag lists after years of clinical review. The goal is to prevent missed diagnoses and keep telemedicine a safe, effective model of care. These rules protect both patients and providers.

Telemedicine is powerful. It expands access and provides convenience. But it has boundaries. When I recommend that a patient be seen in person, it’s because safe, thorough care sometimes needs tools and testing. A video screen simply can’t provide them. When a patient pushes back, I tell them plainly that an in-person evaluation is needed for their own safety. If they keep insisting on staying virtual, I decline and explain that telemedicine has its own standards of care, similar to an in-person visit, built around guidelines that protect patients. Most understand. Not all of them agree.

Dr. Scott Rennie

Tag: primary care telehealth

What Should You Do If a Lab Result in Your Patient Portal Looks Critical?