lab testing in psych

Labs in Psych

Policy & Career Help
Psych Team

Hello there, you have your client in the office, hearing about how everything has gone insane, and immediately feeling overwhelmed. The world may be on fire and sinking in the sand but we still need to rule out additional problems and figure out a plan of care. So this will hopefully be a simple guide about labs/supplements and how to manage them (update, it’ll be additional posts):

The Intake/First Encounter

Even if you have the greatest, easygoing patient, we still need to cover the basics. The reason why the first encounter (or an intake) with patients is so important is to hash out issues immediately. I mentioned some of these assessment points in the kid’s section but they also apply to adults:

  • Any childhood issues or disorders? some people may have conditions that still need to be addressed or could be causing current problems such as frequent infections, incontinence, CA, swelling, thyroid dysfunctions, organ damages/changes, etc., and you want to inquire what the treatment included or the plan to address the issues. It can be a follow-up with PCP, endocrinologist, or a specialist… who will normally get labs so you don’t have to start re-ordering additional tests…
  • When was the last time you saw the PCP or the last time a condition has been addressed? This is also helpful in knowing how compliant the patient will be. If they have e.g. diabetes and don’t regularly check their blood sugar, poor diet, or have other comorbidities, I probably wouldn’t initially start a lithium or antipsychotic regimen.  It’s not a contraindication but something to be mindful of… sidenote: they are people who are adherent but their blood levels are still unstable so just consider the risk vs benefits.
  • When was the last time basic labs were checked? so I will inquire about the PCP (name/number) or practice just in general or for my records. You don’t want this to be just hearsay because this is your evidence that you’re patient has his/her faculties, coherent, not psychotic, etc. and there were no major RED flags to start medications. Yes, we can worry about labs later but in the meantime, we have some kind of green light to start something.
  • My hemoglobin was just a little low. If there was a minor issue with the labs I still inquire about treatment, for example, do you have iron supplements or needed a blood transfusion in the past? is the diet lacking meat? heavy menstrual cycles? do you feel low on energy? so sometimes, a lab history can lead to other issues and I note this in my plan of care/charting. However, the psych provider is NOT managing hemoglobin levels but it can cause other issues that we may need to follow up on… Other implications are based on lab levels.
  • Inquire about substances. This is for my patients that claim they only did a little bit of cocaine last year… Regardless, start a plan of care with regular Rx testing or at least with people with a consistent history. Sometimes I don’t even ask about substances and will say well I have to Rx test you because it’s our standard in the office. Now some patients will confess and you can obtain the drug hx then, but this is primarily based on, if I ask about drugs the patient will assume if they say no, they don’t have to worry about being tested or if they say yes, a person may feel that’s why they will be tested and would lie. However, it doesn’t matter what the patient thinks if we test everyone (because it’s our standard in the office). I’m still going through my substance abuse section but OD fatalities are getting worse and if anyone such as the parents, significant other, or whoever in the household has a drug problem, we don’t want to make it worse. I feel like that’s one of the reasons why drug addictions are taking over is mainly due to a lack of Rx testing. Train teachers, ALL providers, etc. even the parents to Rx test. Overall, diversion and ODs are a real problem so we may have to wait on prescribing scheduled medications but at least there are still many other great options to help the patient.

…Basically, I don’t want to reinvent the wheel and the intake is key to what was already taken care of versus current problems.  If blood levels were never checked, the patient is young, or you have this clean slate you still have several options to consider before ordering a baseline.

  • Ask the patient if they’re interested: I know this is controversial but with COVID, telehealth, less income, and having fewer options. I don’t worry about labs unless the patient is pissing blood. Encourage them to follow up with ER/PCP but it’s not a deal-breaker to start medications.
  • What’s the purpose of treatment? If I’m weaning a patient off their medications, maybe just starting, or dosages are so low that I normally don’t worry about getting labs but I know this could be RARE.
  • “Our Clinic Doesn’t Do Labs” This is why documentation is so important because this will not hold up in court. Labs may not be mandatory but discuss how it’s helpful and the risks/benefits of medications if the patient continues to refuse then express that some medications will not be prescribed, and DOCUMENT the refusal but order what you can or what you feel comfortable with… If the patient agrees, write out on a prescription pad (or eprescribe) the following information so the patient can go to the nearest care center:

Write the ICD code at the top (Disruptive Mood Dysregulation Disorder DX: F34. 81 i.e. or whatever disorder) and write “please fax results” to your office/clinic at the top of the prescription pad note. What to monitor or obtain (written either on 2 separate prescription notes or however it’s ordered at your facility):

  1. Labs: TSH; Free T4; HgbA1C; CMP; CBC w/Diff; UA; Urine Toxicology Serum, & Pregnancy Test (for child-bearing women)
  2. EKG r/o arrhythmia or prolonged QTc (this is usually written separately with the ICD code information at the top)

–Psych Charts and Tables

Quick Sidenote: outpatient/urgent care clinics normally don’t do height, weight, BMI, or maybe it can be a courtesy task but you don’t put that in the prescription pad…sometimes I’ll just ask the patient what’s there pants/dress size if they don’t know their measurements. Last sidenote: for telehealth and community mental health, labs and various measurements may be a requirement (the state pays based on quotas) so always check you’re policy/protocols. Private practice has the most flexibility, thus fewer requirements but usually doesn’t have high acuity patients…

About Baselines

Getting labs, however, is truly the gold standard for complicated situations. If my patient is a young healthy child/adult, I’m not too worried about bloodwork. If you have to start meds regardless of the bloodwork, then start the medication(s) low and go up slow. I usually start this way unless I inherited someone on different dosages. However, if the patient simply doesn’t want to (document the refusal as well), proceed with caution. Here are some examples, in which I would definitely need to establish some kind of baseline:

  • Atypical side-effects or symptoms of mental or medical conditions
  • Worsening mental health i.e. hallucinations, depression, somatic complaints, personality/borderlines, memory/cognitive problems
  • Certain regimens such as lithium, clozapine, SGA’s, scheduled medications, or drugs that may cause organ dysfunction i.e. duloxetine (liver damage)
  • Chronic conditions, neurodevelopmental disorders (also because communication may be difficult), or liver/kidney/heart dysfunctions
  • PREGNANCY

Thankfully, some of the above situations usually already have established providers or lab work so just request records or inquire about/note any abnormalities. Now we can go over labs real quick.

    Lab Levels

The complete metabolic panel (CMP) is preferred because it includes the liver and protein data. The Basic Metabolic Panel (BMP) is just that, basic, and mainly covers your major electrolytes. If you get labs, we don’t want multiple pokes so don’t use the BMP plus we have to know if the liver is doing okay. It’s also recommended to fast 12 hours prior if possible –Psychiatry News (and other requirements).

A baseline for meds that can affect organ function:

  • ECG/baseline QT interval: stimulants, some SGAs/antidepressants
  • Electrolytes (Ca+, Na+, Zn+ RBC, Mg+ RBC): SSRI/SNRIs, anticonvulsants
  • CBC w diff: anticonvulsants, some antipsychotics
  • HCG: pregnancy
  • Kidney: lithium, SSRI’s/SNRI’s
  • Lipids/blood glucose: antipsychotics
  • Liver: anticonvulsants, some antidepressants, SUD tx meds
  • Thyroid function/serum iodine: lithium

U/A: r/o infections, substances, dehydration, ketones, blood

References and Additional Information 

A Different Perspective

I came across this interesting read about not ordering extra labs in psych and it got some good key points BUT notice the article is somewhat outdated. Also, be mindful of how providers can get sued for not managing the side effects or the complications r/t psych medications (not just for recording abnormal levels and not addressing them as the article below suggests). Nevertheless, this is truly the general consensus with outpatient clinics:

Screening Labs for New Patients: Are They Useful?

Dr. George Lundberg, former editor-in-chief of JAMA and current editor of Medscape General Medicine, once cautioned physicians against the excessive use of routine labs: The more lab tests that are done, the greater the chance for an abnormal result, whether or not the patient is sick (see http://www.medscape.com/viewarticle/495665 –link is not found).

In psychiatry, we typically order screening labs on new patients for a variety of purposes, including to rule out medical causes of psychiatric symptoms, to record baseline data before prescribing medications that may lead to lab abnormalities, and to screen for general medical problems. What labs should we order for new patients? A literature review yields very little hard data to guide decisions, so what follows is a combination of research-based recommendations and common clinical sense.

General Guidelines

  1. Before you order any labs, think about what you intend to do about the results. As psychiatrists, we need to be realistic about whether we have kept up on the current general medical literature. There are significant liability issues if you order many labs but are not up to date in the art of interpreting them. Once the numbers are in your chart, you own them and can be sued for malpractice if you don’t follow up any abnormal values appropriately.
  2. Rather than ordering screening labs, it is more important to make sure your patient is receiving appropriate health maintenance care from a primary care physician. National guidelines for adult preventive care are complicated and are updated yearly. For example, from age 21 to 50, current guidelines recommend that all patients should see their PCP every one to three years; after age 50 it should be annual. Depending on variables such as gender, age, and other risk factors, all your patients should be receiving regular screening tests such as breast exams, pelvic exams, pap tests, fecal occult blood tests, testicular and prostate exams, and skin exams for melanoma. The bottom line is: Don’t fool yourself into believing that you are fulfilling the role of a PCP by simply ordering some lab tests.

Brief Research Review and Recommendations

The best reason for psychiatrists to routinely order a battery of tests is to provide a baseline in case you need to prescribe a medication that can cause lab abnormalities. Common psychiatric medications can cause abnormalities in the complete blood count (CBC) (anticonvulsants, some antipsychotics), electrolytes (SSRIs, anticonvulsants), kidney functions tests (lithium), thyroid function tests (lithium), lipids (antipsychotics), and liver function tests (anticonvulsants, some antidepressants). Thus, one can argue that you should order this entire battery of tests just in case your patient ends up on one of these meds.

A more common rationale for ordering baseline labs is to screen for potentially treatable medical conditions that might contribute toward a psychiatric presentation.

There have been very few studies done to evaluate the utility of this practice. The first comprehensive review (Anfinson TJ et al., Gen Hosp Psychiatry 1992;14:248-257) concluded that screening labs often reveal abnormalities in patients who: 1. Are inpatients, particularly in state hospitals and VAs; 2. Have low socioeconomic status [SES]; and 3. Have poor outpatient follow-up. In these populations, the medical problems revealed by screening labs were consequences of poor health care but were unlikely to be causes of psychiatric illness. Such patients require thorough physical exams, review of systems, and lab testing in order to pick up on a variety of medical problems. But studies focusing on general inpatient units, in which high proportions of patients had private insurance, found much lower rates of clinically significant lab findings, ranging from 0.8% to 4%. Synthesizing all the studies, the authors reported that the most useful tests for a limited screen for inpatients were serum glucose, electrolytes, BUN, creatinine, and urinalysis.

A more recent review (Gregory RJ et al., Gen Hosp Psychiatry 2004;26:405- 410) also found low yields of abnormal labs when they were ordered indiscriminately for psychiatric inpatients. Combining the results from eight studies, they reported the following rates of clinically significant lab abnormalities: CBC, 2.2%; urinalysis, 3.1%; electrolytes, 1.7%; thyroid function tests, 2.1%; B-12, 5.7% (this was based primarily on the results from a single study); RPR/VDRL, 0.3%. Looking more closely at some of the subpopulations of these studies, the authors concluded that labs for inpatients should be reserved for those with high pre-test probabilities of having a medical illness, including the elderly, substance users, patients with no prior psychiatric history, and patients who present with clear histories of prior medical problems.

As you can see, the focus of all of these studies is on inpatients, providing little guidance for the majority of psychiatrists, who see primarily outpatients. I found only two studies focusing on outpatients, and both tested the utility of ordering a TSH (thyroid-stimulating hormone) in outpatients presenting with major depression. The yield of cases of clinical hypothyroidism was very low. In a series of 200 outpatients with major depression, there were no overt cases of hypothyroidism, and there were 5 (2.6%) cases of subclinical hypothyroidism. All patients were treated openly with Prozac, and there was no relationship between response rate and thyroid status (Fava M et al., J Clin Psych 1995 May; 56(5):186-192). In a larger series of 725 geriatric outpatients with depression, only 5 patients (0.7%) had high TSH levels, and patients with elevated TSH did not differ from patients with normal TSH in the severity or symptom pattern of depression (Fraser SA et al., Gen Hosp Psychiatry 2004;26:302-309).

Bottom Line Recommendations for Screening

  1. For inpatients or outpatients of low SES [socioeconomic status] and low rate of outpatient medical care: Obtain a medical consultation for health care maintenance evaluation. If this is not available in your setting, do your own physical exam, conduct a careful medical review of systems, and order a full battery of screening tests: CBC, electrolytes, BUN, creatinine, glucose, lipid panel, liver function tests, thyroid function tests, B12, urinalysis. For those at higher risk for STDs, order VDRL.
  2. For inpatients of higher SES with private insurance: Obtain medical consultation from the patient’s PCP, or if this is not readily available, obtain a list of recent lab results. Get limited screening battery: serum glucose, electrolytes, BUN, creatinine, and urinalysis.
  3. For outpatients of higher SES with private insurance: Unless you are planning to start medications that may cause specific lab abnormalities, do not order any labs, and ensure that the patient receives basic recommended health care maintenance visits with a PCP.

TCPR VERDICT: Screening labs: Reserve them for poor inpatients.

–Psych Central (Last medically reviewed on August 26, 2013)

In Conclusion 

I don’t agree with the verdict of reserving labs for the “poor inpatients” lol like I can’t believe this was published because it’s somewhat offensive. Reserve labs when you can justify the reason such as medication regimens, side-effects, medical issues, r/o other conditions, worsening of mental health…etc. and some reasons listed above but not just because of SES.

Some of my riskiest psych patients are physically healthier than rich/normal people. I do agree with the article encouraging patients to f/u with PCP for regular health screenings and the other key parts…but the point I wanted to make real quick is how there’s NOT much written in stone.  However, try to make your standard of practice erring on the side of caution and DOCUMENT. I hope this post was helpful!

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