Part III of our Underwriting Liver Function Blog Series:
If you tuned into part II of this liver function series, you had the chance to join the first half of our sing-a-long playlist. And more importantly, learn some of the key tests underwriters should be aware of when working on liver function cases. Now, let’s wrap up this sing-a-long with a final list of tests all underwriters should reference when underwriting liver function. Get your vocal cords ready!
Mean Corpuscular Volume [Hello – Adele]
Hello, it’s mean corpuscular volume. I was wondering if after all these years you’d like to meet. To go over everything. For starters, you can call me MCV. Okay, okay enough with the lyrics – we’re having fun though right?! Getting back on track, MCV is just a dividend of the hematocrit (the proportion of cellular blood in blood volume) and red blood cells (RBC) counts in that volume. Simple arithmetic, yes? It’s an important part of the standard complete blood count (CBC) though, as it can easily differentiate between microcytic anemias (low MCV), normocytic anemias (normal MCV), and macrocytic anemias (high MCV, bet you couldn’t guess that, eh).
What can a high MCV imply?
A high MCV is particularly telling though, due to its association with liver disease and alcohol abuse. But lastly, a caveat: RBC can cause fictitious elevations in the MCV. Swelling is generally caused by delays between sample collection and sample testing, during which the blood specimen rests in a tube. While this may not be problem for hospitals where blood is both collected and tested onsite, it could very well be an issue on insurance lab testing, which use third-party laboratories. A quick and reliable way to tell if an MCV elevation could be fictitious or not would be to look at the ratio of hemoglobin to hematocrit on the CBC – it should be 1:3, roughly. If the ratio is terribly off though, then it is likely that there is a problem with the sample.
Alpha-fetoprotein [Baby – Justin Bieber]
When you think alpha-fetoprotein (AFP), or α-fetoprotein if we’re going Greek, you can think of Bieber singing ‘baby, baby, baby ohhhh’. Why? AFP is a major plasma protein produced by the liver of a fetus during early development. It’s most commonly seen being monitored in the medical records of pregnant women who, to no one’s surprise, show elevations in AFP. It’s used in this context as a screening test for genetic and other abnormalities that may arise in the fetus; but to the pregnant woman herself, it’s not a concern at this point. So what’s the relevance here? Simply put, it makes a great tumor marker for screening purposes later in life.
If you aren’t a fan of Bieber, I have good news. AFP goes beyond pregnancy as well. In adults (pregnancy aside), AFP should only be found in very low levels; however, certain cancers will cause elevations. We speak mainly of liver cancers here; germ cell tumors perhaps deserve a mention, but they are rare. Because of the association with liver cancers though, AFP is must-have test for monitoring clients with a known history of liver cirrhosis. We should see it monitored in cases of chronic Hepatitis C as well, given this virus’ propensity (more so than Hep B) to lead to complications of cirrhosis and liver cancer.
Prothrombin Time/ International Normalized Ratio [Hung Up – Madonna]
Time goes by so slowly. And in the case of a prothrombin time (PT) test, were looking at the average time it takes for the blood to form clots. The international normalized ratio, or INR, is a representation of the PT that allows for comparisons between different laboratories. You will most often see the INR being monitored in the medical records of a client who is on anti-coagulant medication, such as Coumadin/Warfarin. For these patients, it is expected that the INR will be higher than normal given the use of such pharmacologic agents which inhibit blood clot formation.
However, INR is also an underappreciated liver function test. Fibrinogen, one of the proteins that helps to form blood clots, is produced in the liver. Liver diseases that impair the production of this molecule will therefore be detectable on INR testing. This also makes INR a useful test for monitoring the liver function in patients with a known impairment, such as hepatitis or cirrhosis. Clients with high, particularly worsening INR times where there is no anti-coagulant treatment, should be interpreted as unfavorable risks.
Remember to look at each case holistically
My goal with this sing-a-long (aside from getting some classic songs stuck in your head) was to demonstrate the value of using all tests available to you as an underwriter. One abnormal test alone may point to a liver problem, but it may also be misleading. Look at each case holistically, and when possible be sure to incorporate imaging studies into your risk evaluation. Liver ultrasounds, CT/MRI scans, and the relatively new FibroScan studies all play an important role in diagnosing the problems uncovered on laboratory testing – make use of them when available!