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Laboratory Testing–General Articles
12 “sins” in laboratory testing in mental health
ICD-10 diagnostic codes for laboratory tests
Is it essential to be fasting for lab tests?
Biotin can interfere with many laboratory tests and lead to serious misdiagnosis
When patients tell us that a test result or their blood pressure was “normal”
Which laboratory tests should we order in various situations?
What laboratory tests should a mental health clinician order and when?
Clinicians’ guide to screening tests in mental health
What should I be doing to monitor patients who are on an antipsychotic?
Which laboratory tests should be done in persons taking valproate/ divalproex (Depakote-ER®)?
Which laboratory tests in persons with first-episode psychosis?
Which laboratory tests in men with erectile dysfunction?
A primer on tests for identifying 2019 novel coronavirus (SARS-CoV-2) infection
Alcohol use—Laboratory tests
How to use laboratory testing for alcohol use
Phosphatidylethanol (PEth) testing to identify recent alcohol use
How do PEth and CDT tests compare for identifying recent alcohol use?
Abstinence from alcohol can be monitored by a urine screening test
Tips about hepatic function tests
Real-life examples: How to identify recent alcohol use in urine and blood tests
Can thrombocytopenia be due to alcohol use?
Basic metabolic panel (BMP, Chem 7)
Also see: Kidney (Renal) Function Tests
How to know if the BUN and creatinine are elevated due to dehydration
How to calculate the corrected serum calcium
Metabolic acidosis: A primer
How to monitor for possible metabolic acidosis
What is the anion gap and how can we easily calculate it from the lab results?
Complete blood count (CBC)
Why we sometimes specifically order a “CBC with differential”
A primer on the Absolute Neutrophil Count (ANC)
Can thrombocytopenia be due to alcohol use?
A patient with elevated WBC, absolute neutrophil, and platelet counts
How is beta-thalassemia minor relevant to mental health clinicians?
C-reactive protein
Electrocardiogram (ECG)
When to do an electrocardiogram (ECG or EKG)
How often should we order ECG (EKG) during treatment with a psychotropic medication?
Does this drug cause QT prolongation and torsades?
Antipsychotics and QT prolongation
Antibiotics, antipsychotics, and QT prolongation
Hydroxyzine (Vistaril®, Atarax®) and QTc prolongation
SSRIs and QT prolongation
Can mirtazapine increase the risk of QT prolongation?
Lithium’s effects on the electrocardiogram (ECG, EKG)
Hemoglobin A1c (HbA1c)
Why I screen for hyperglycemia using hemoglobin A1c (HbA1c)
What can cause a falsely elevated or low hemoglobin A1c (HbA1c)?
What exactly is “prediabetes” and why is it so important?
Hepatic (Liver) function tests
Hepatic (Liver) Function Tests—General Articles
How to order and interpret hepatic (liver) function tests
Hy’s law: When liver enzyme elevation may be *extremely* serious
Three benzodiazepines are safer in the elderly and in liver disease
Hepatic (Liver) Function Tests—Alcohol Use Disorder
How to use laboratory testing for alcohol use
Real-life examples: How to identify recent alcohol use in urine and blood tests
Why and how to calculate the FIB-4 score in asymptomatic alcohol-associated liver disease
Hepatic (Liver) Function Tests—Liver Enzymes
Hy’s law: When liver enzyme elevation may be *extremely* serious
Elevated alkaline phosphatase
Hepatic (Liver) Function Tests—Total Protein, Albumin, Globulin
What could a high or low albumin-globulin ratio mean?
Hepatic (Liver) Function Tests—Plasma Ammonia
False-positive elevation of plasma ammonia
Valproate (Depakote®) and elevated serum ammonia level (hyperammonemia)
Hormone levels
Should we look at serum FREE testosterone or TOTAL testosterone?
Exactly which test should we order to measure free testosterone?
Should we be checking testosterone levels in older men?
Should we check testosterone levels in men with “treatment-resistant” depression?
Iron studies
Laboratory testing to identify iron deficiency
How to order and interpret iron studies
What is the best single test for checking the body’s iron stores?
Restless Legs Syndrome (RLS) and iron deficiency
Are we missing iron deficiency without anemia?
Management of iron deficiency
Instructions for WHEN and HOW to take iron supplements
How to maximize absorption of iron supplements
How to improve the tolerability of iron supplementation
Which foods are rich in iron?
Iron deficiency, pica, and restless legs syndrome associated with blood donation
Let’s ask about heavy menstrual bleeding
Kidney (Renal) Function Tests
General Articles
How to know if the BUN and creatinine are elevated due to dehydration
What are the stages of chronic kidney disease?
Serum creatinine
What serum creatinine is and why it is important
What factors may affect the serum creatinine level?
How to know if the BUN and creatinine are elevated due to dehydration
Can creatine supplements lead to “false” elevation in serum creatinine?
Why it is important to longitudinally chart serum creatinine and eGFR values
Another way in which charting serum creatinine values can be helpful
Automatic calculators for eGFR using creatinine, cystatin C, or both
Recommended app for calculating eGFR in adults and youth
Serum cystatin C
Should we routinely use cystatin C to evaluate kidney function?
Automatic calculators for eGFR using creatinine, cystatin C, or both
Recommended app for calculating eGFR in adults and youth
Checking urine albumin/creatinine ratio and serum cystatin allowed lithium to continue
Estimated Glomerular Filtration Rate (eGFR)
What is the estimated GFR (eGFR)?
Useful tip about the next step when eGFR is low
Why it is important to longitudinally chart serum creatinine and eGFR values
Another way in which charting serum creatinine values can be helpful
Should we routinely use cystatin C to evaluate kidney function?
Automatic calculators for eGFR using creatinine, cystatin C, or both
Recommended app for calculating eGFR in adults and youth
Urine protein/albumin/microalbumin
In suspected kidney disease, check the urine albumin-creatinine ratio
Useful tip about the next step when eGFR is low
Checking urine albumin/creatinine ratio and serum cystatin allowed lithium to continue
Creatinine clearance
24-hour urine for creatinine clearance
How to collect a 24-hour urine sample
Lipid panel
The lipid panel (profile): Why, when, and how to order it
What should I be doing to monitor patients who are on an antipsychotic?
Liver Function Tests—see “Hepatic Function Tests”
Medication levels
Medication levels: General
How many days to wait before measuring the blood level of any medication
When to measure serum levels of mood stabilizers
Clomipramine levels
When and how to check the clomipramine level
How to interpret clomipramine and desmethylclomipramine levels
Clozapine levels
Lamotrigine levels
Lamotrigine level and adverse effects
Timing of blood draw for a serum lamotrigine level
How many days to wait before checking a steady-state lamotrigine level
Lithium levels
If serum lithium levels vary unexpectedly, consider these possible causes
Lithium augmentation in major depressive disorder: How much?
Nortriptyline levels
Oxcarbazepine levels
Valproic acid levels
Neuroimaging
Pharmacogenetic testing
Serotonin transporter promoter region
Serotonin transporter linked polymorphic region (5-HTTLPR)
5-HTTLPR and efficacy of antidepressants
5-HTTLPR and adverse effects of antidepressants
5-HTTLPR and antidepressant-induced mania
Serotonergic receptors
Serotonin 2A receptor gene (HTR2A) polymorphisms and adverse effects
HTR2C polymorphisms and medication-induced weight gain
Blood-brain barrier/ P-glycoprotein
Cytochrome P450 enzymes
HLA gene testing
Melanocortin 4 receptor (MC4R)
Commercially-available pharmacogenomic tests
(listed alphabetically)
CNSDose® (CNSDose, LLC)
Genecept assay® (Genomind, LLC)
GeneSight® pharmacogenomic test batteries (Assurex Health)
Commercially available pharmacogenomic test panels
Miscellaneous
Renal Function Tests—see “Kidney (Renal) Function Tests”
Prolactin
Thyroid function tests
Urine Drug Screening
Urine Drug Screening–General Articles
Which urine drug screen (UDS) should we specifically order?
Which urine drug screen do most workplaces require?
For how long are substances detected in a urine drug screen (UDS)?
Opioids in the urine drug screen
“Fingerprint” metabolites that uniquely identify substances in a urine drug screen
Urine Drug Screening–False Positives
False-positive urine drug screen: Principles and a table for reference
Urine Drug Screening–False Negatives
Standard urine drug screens can be false-negative for some benzodiazepines
Will zolpidem be detected on a standard urine drug screen?
Urine Drug Screening–Fentanyl
Special tests are needed to identify fentanyl in the urine
Use and recommend an FDA-cleared over-the-counter fentanyl urine test
Why and how to use fentanyl test strips
Vitamin levels
General articles
Testing for B vitamins in patients with cognitive impairment
Folate
Serum folate is not the right test to order
Homocysteine
Interpreting combinations of methylmalonic acid and homocysteine level results
Vitamin B12
How to evaluate a person’s vitamin B12 status
Vitamin B12 and mental health
Testing for B vitamins in persons with cognitive impairment
A patient with a low vitamin B12 level
Which supplements to recommend with a vegetarian or vegan diet
Elevated vitamin B12 levels are common and could be very serious
Vitamin D
What is vitamin D?
How should vitamin D status be measured?
Don’t order the test “calcitriol (1, 25-dihydroxy vitamin D)”
How to interpret the results of testing for vitamin D deficiency
How should we define vitamin D insufficiency (deficiency)?
How should vitamin D insufficiency or deficiency be treated?
Does vitamin D supplementation increase the risk of kidney stones?
Ultraviolet A and B: Implications for vitamin D production
Miscellaneous
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