Article

CLINICAL: INTERDISCIPLINARY

FACILITATE LAB TEST ORDERING

COORDINATE WITH PRIMARY CARE PHYSICIANS FOR DISEASE MANAGEMENT

OCULAR MANIFESTATIONS of systemic disease are frequently encountered in our practices. The proper medical labs are necessary to confirm the diagnosis and initiate proper management. (See “Table 1,” p.39.)

TABLE 1
COMMON LAB TESTS POSSIBLE OCULAR MANIFESTATIONS
Complete blood cell (CBC) count with differentials (diff); (Red blood cell count (RBC), white blood cell count (WBC) with diff, hemoglobin, hematocrit, RBC indices, platelet count) Manifestations of anemia, leukemia, bacterial, inflammation or bleeding disorders (such as retinal vasculopathy)
Lipid profile low-density lipoprotein (LDL)/high-density lipoprotein (HDL)/triglyceride (TG)/very low-density lipoprotein (VLDL)/cholesterol Cardiovascular disease risk factors, such as retinal emboli, atrial fibrillation/transient ischemic attack, retinal artery occlusion, anterior ischemic optic neuropathy, arcus and xanthelasma.
Fasting blood sugar (FBS)/HbA1c Diabetes mellitus (i.e. diabetic retinopathy)
Inflammatory markers (Erythrocyte sedimentation rate (ESR)/c-reactive protein (CRP) Adjunct to ocular manifestations of giant cell arteritis and ocular manifestations of inflammatory or autoimmune disease (i.e. uveitis)
Rheumatoid factor (RF) Arthritic ocular manifestations (i.e dry eyes)
Angiotensin-converting enzyme (ACE) Adjunct to ocular manifestations of sarcoidosis
Blood clotting tests (Prothrombin time (PT)/partial thromboplastin time (PTT)/international normalized ratio (INR)) Manifestations of coagulation disorders (i.e CRAO) in a young patient)
Thyroid testing (Triiodothyronine (T3)/ thyroxine (T4)/thyroid stimulating hormone (TSH)) Thyroid-related ocular manifestations (i.e. Grave’s disease)
Sickle cell testing “SCD” (Sickledex) Ocular manifestations of SCD (i.e. peripheral neovascularization)
Antinuclear antibody (ANA) Autoimmune disease screener (i.e. adjunct to lupus)
Human leukocyte antigen (HLA) Specific autoimmune disease (i.e. ankylosing spondylitis-related uveitis)
HIV-Elisa HIV-related ocular manifestations (i.e. Kaposi sarcoma)

When encountering a particular ocular finding, there may be a plethora of tests considered. A comprehensive eye exam and a detailed history helps narrow down the differential diagnoses, aiding in determining which medical blood tests should be ordered.

For example, a patient with a recurrent subconjunctival hemorrhage and no contributing history of risk factors, such as medications or medical history, may have a hematological disorder. To find out, however, he must undergo a complete blood cell count (CBC) with differential, liver function tests, prothrombin time, partial thromboplastin time and international normalized ratio (INR) tests, in addition to in-office blood pressure measurement and a consultation with his primary care physician (PCP). When the latter occurs depends on your state scope-of-practice laws. Work with the primary care physician and a lab to meet the needs of your patients.

PROHIBITED FROM ORDERING

If your state scope-of-practice laws and/or the patient’s insurance prevent you from ordering medical lab tests, contact the patient’s PCP to inform him or her of the ocular finding you believe is related to a particular systemic disease. This way, the PCP can order proper medical lab testing, enabling you to ensure the patient receives the most appropriate treatment fast. Specifically, provide a summary report to help the PCP understand the ocular condition; this may include pertinent data related to the case.

For example, the most critical part of managing an older patient who has a central retinal artery occlusion (CRAO) is to order a hypertension panel, diabetes mellitus and lipid profile, transesophageal or transthoracic echocardiogram, carotid doppler, CBC with differential and erythrocyte sedimentation rate (ESR)/c-reactive protein (CRP) tests.

If the PCP is aware of the close correlation between stroke and CRAO, he or she may order an MRI or neurological consult. (According to the American Stroke Association and the American Heart Association, there is a high risk of subsequent stroke following the incidence of a CRAO.)

The PCP then shares with you, the optometrist, the results of the requested medical lab tests. A follow-up visit is scheduled with the patient to discuss the results, if necessary, and any ocular ramifications. The PCP manages the underlying disease.

Depending on scope of practice laws in your state, you may coordinate directly with a lab or with the patient’s primary care physician.

FREE TO ORDER

Should you be able to write a request for lab tests, use a pre-printed order lab form or a transmission through your EHR system. Be sure to document on the form or via the transmission a proper ICD-10 code (this may include systemic condition and/or ocular finding/diagnosis).

Providing a “rule-out” diagnosis is generally not accepted by insurance, but if you suspect a particular condition, you can use that disease code as a differential diagnosis and order the proper tests. For example, one could write “ACE” to “r/o Sarcoidosis” rather than listing a number of medical lab tests and then state “r/o TB, syphilis, toxoplasmosis, etc.”

As is the case when prohibited from ordering tests, contact the patient’s PCP about your findings and their possible link to a systemic disease.

Regardless of which camp you’re in, coordinating care with the PCP provides him or her with an understanding of how systemic disease relates to the eye, again, enabling the order of the proper lab tests, which expedites correct patient care and helps build referrals to your practice. In addition, the PCP will ultimately be managing the underling disease.

MAINTAIN COMMUNICATION

Continuous communication with PCPs is critical to patient care. Do so by providing them with information about your ocular management and follow-up. With our scope of practice expanding, ordering proper lab tests, in conjunction with the PCP, helps to re-define our role within health care. OM