PMHNP Lab Guide

I. Introduction

A. Importance of laboratory tests for PMHNPs

It’s obvious that lab tests are important & that they play a critical role in psychiatric care. They provide psychiatric practitioners with essential information for diagnosis, treatment planning, and monitoring patient progress. Some lab tests are required prior to starting a medication, some will help to recognize negative side effects of others. They may help to identify medical conditions which are actually to blame for the patient’s psychiatric symptoms.

For many, PMHNP education lacks depth & is truly elementary as it relates to the understanding of lab tests. PMHNPs are responsible for managing complex treatment plans, a thorough understanding of laboratory tests and their interpretation is essential to delivering safe and effective patient care.

B. Overview of common lab tests and their relevance to psychiatric care

There are numerous lab tests that PMHNPs should be familiar with, as these tests can offer insights into a patient's overall health and well-being, as well as inform decisions about medication management. Some common lab tests relevant to psychiatric care include:

1. HbA1c: Provides information about blood sugar control and is important for managing patients with diabetes or prediabetes, conditions that may coexist with psychiatric disorders.

2. Electrolytes (sodium, potassium): Essential for proper nerve and muscle function, and can be affected by certain psychiatric medications.

3. Prolactin: May be elevated due to certain antipsychotic medications, leading to potential side effects.

4. Liver function tests (ALT, AST, LFTs): Help monitor the impact of medications on liver health.

5. Thyroid function tests (TSH): Assess thyroid function, as thyroid disorders can contribute to mood and cognitive symptoms.

6. Ammonia: Elevated levels can indicate liver dysfunction, which may contribute to neuropsychiatric symptoms or be related to medication side effects.

7. Lipid profile: Monitors cholesterol and triglyceride levels, which can be affected by some psychotropic medications and are essential for assessing cardiovascular risk.

8. Complete Blood Count (CBC) and Absolute Neutrophil Count (ANC): Evaluates overall blood cell health and monitors potential side effects of certain medications, such as agranulocytosis.

9. Kidney function tests (GFR, BUN, Creatinine): Assess kidney health and help determine medication dosing adjustments based on renal function.

10. Cortisol: Provides information about stress response and adrenal function, which can be relevant in certain psychiatric conditions like major depressive disorder.

11. Electrocardiogram (EKG): Evaluates cardiac function and monitors potential side effects of medications on heart rhythm, such as QT interval prolongation.

By understanding and interpreting these common lab tests, PMHNPs can provide comprehensive care to their patients, addressing both their psychiatric and physical health needs. This knowledge also helps PMHNPs make informed decisions about medication management and recognize potential side effects or drug interactions. Next we will dig into each of these lab tests.

II. Lab Tests and Their Interpretation

A. HbA1c

Explanation and importance

Hemoglobin A1c (HbA1c) is a blood test that reflects a person's average blood glucose levels over the past three months. It is used to diagnose and monitor diabetes or prediabetes, as well as assess how well a person's diabetes is being managed. A higher HbA1c level indicates poorer blood sugar control, increasing the risk of diabetes-related complications. In psychiatric care, it is essential to monitor HbA1c levels because diabetes and psychiatric disorders, such as depression and bipolar disorder, often coexist, and certain psychotropic medications can affect blood sugar levels.

Medication classes affecting HbA1c

Several medication classes used in psychiatric care can impact blood sugar levels and HbA1c, including:

• Atypical antipsychotics: Some atypical antipsychotics, such as olanzapine and clozapine, have been associated with an increased risk of elevated blood glucose levels and the development of diabetes.

• Antidepressants: Some antidepressants, particularly tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs), may cause slight elevations in blood sugar levels in some individuals.

Symptoms and presentation of abnormal HbA1c levels

Patients with elevated HbA1c levels may present with symptoms of hyperglycemia, which can include:

• Increased thirst

• Frequent urination

• Fatigue

• Blurred vision

• Slow-healing wounds or frequent infections

• Unintended weight loss

It is important to recognize these symptoms in patients who are taking medications known to affect blood sugar levels. In some cases, adjusting the medication regimen or adding appropriate treatment for diabetes may be necessary.

On the other hand, patients with low HbA1c levels may experience symptoms of hypoglycemia, although this is less common in the context of psychiatric care. Symptoms of hypoglycemia can include:

• Trembling or shaking

• Sweating

• Rapid heartbeat

• Dizziness or lightheadedness

• Confusion

• Irritability or mood swings

• Hunger

• Headaches

Regular monitoring of HbA1c levels in patients at risk for or diagnosed with diabetes is essential for optimal psychiatric care.

B. Electrolytes